The Organometallic Chemistry of Ambident Acetone Dianions.
Reactions with Group 4 and 14 Element Dihalides.
By
Tao Wang
B.S., Chemistry
Hefei Polytechnic University, 1982
M.S., Chemistry
Southern Methodist University, 1990
Submitted to the Department of Chemistry in Partial
Fulfillment of the Requirements for the Degree of
Doctor of Philosophy
at the
Massachusetts Institute of Technology
February!9'3
© Massachusetts Institute of Technology 1995
All rights reserved.
Signature of Author
-"- Department of Chemistry
November 14, 1994
Certified by
/
/
n
Dietmar Seyferth
X
__IThesis Supervisor
I/ v
Accepted by
//
Dietmar Seyferth, Chairman
Departmental Committee on Graduate Students
rrsE@e~.sli
2
This doctoral thesis has been examined by a Committee of the Department of Chemistry
as follows:
Professor Hans-Conrad zur Loye
_I
_
r9
.N
Professor Dietmar Seyferth
-
Chairman
I
~~~/
Thesis Supervisor
A9
Professor Richard R. Schrock
3
The Organometallic Chemistry of Ambident Acetone Dianions.
Reactions with Group 4 and 14 Element Dihalides.
By
Tao Wang
Submitted to the Department of Chemistry on November 14, 1994 in
partial fulfillment of the requirement for the degree
of Doctor of Philosophy
ABSTRACT
Chapter One. Reactions of Group 4 Metallocene Dichlorides with Acetone Dianions
Acetone dianions, [CH2C(O)CR 2 ] 2 - (R = Ph, H) react with group 4 metallocene
dichlorides (M = Zr, Hf) as C, O dinucleophiles. The products in solution are (by VPO)
monomeric 2-metallaoxa-3-methylenecyclobutanes,
but in the solid state they are "dimers",
1,5-dimetalla-2,6-dioxa-3,7-dimethylenecyclooctanes. The structure of 1,1,5,5tetrakis(rl 5 -cyclopentadienyl)-3,7-bis(diphenylmethylene)-
1,5-dizircona-2,6-
dioxacycloocetane was determined by X-ray crystallography.
Chapter Two. Reactions of Organosilicon Halides with the Ambident 1,1Diphenylacetone Dianion
1,1-Diphenylacetone dianion reacts with diorganodichlorosilanes
to give 1,1,5,5-
tetraorgano-3,7-bis(diphenylmethylene)-1,5-disila-2,8-dioxacyclooctanes, while 1,1diphenylacetone dianion reacts with diorganodifluorosilanes to give a positional isomer,
1,1,5,5-tetraorgano-3,7-bis(diphenylmethylene)-1,5-disila-2,6-dioxacyclooctane. The
structures of 1,1,5,5-tetraphenyl-3,7-bis(diphenylmethylana)-1,5-disila-2,8dioxacyclooctane and 1,1,5,5-tetraphenyl-3,7-bis(diphenylmethylana)-1,5-disila-2,6dioxacyclooctane were determined by X-ray crystallography. A ten-membered cyclic
comound and a six-membered cyclic compound also were prepared by the reaction of 1,1diphenylacetone dianion with 1,2-dichlorotetramethyldisilane and 1,3-
dichlorohexamethyltrisilane, respectively. The structure of 1,1,2,2,6,6,7,7-octamethyl-
4
4,9-bis(diphenylmethylene)-1,2,6,7-tetrasila-3,10-dioxacyclodecanewas determined by Xray crystallography.
Chapter Three. Reactions of Diphenylgermanium Dihalides with the Ambident 1,1Diphenylacetone Dianion
l,l-Diphenylacetone
dianion reacts with diphenyldichlorogermane and
diphenyldifluorogermane to give 1,1,5,5-tetraphenyl-3,7-bis(diphenylmethylene)-1,5digerma-2,6-dioxacyclooctane. The structure of 1,1,5,5-tetraphenyl-3,7bis(diphenylmethylene)-1,5-digerma-2,6-dioxacyclooctanewas determined by X-ray
crystallography.
5Chapter Four. Synthesis and Characterization of 1,1'-11
Bis(Dimethylvinylcyclopentadienyl)
Group 4 Metal Dichlorides
Lithium dimethylvinylsilylcyclopentadienide
reacted with Group 4 metal chlorides
to afford 1,1'-bis(dimethylvinylsilylcyclopentadienyl)group 4 metal dichlorides in good
yield. In addition, o-1,l'-bis(dimethylvinylsilyl)benzene and 1,1'bis(dimethylvinylsilyl)ferrocenealso were prepared. These monomers potentially could be
used for cyclopolymerization.
Thesis Supervisor: Dr. Dietmar Seyferth
Title: Professor of Chemistry
5
TABLE OF CONTENTS
3
ABSTRACT .................................................................
Chapter One. Reactions of Group 4 Metallocene Dichlorides with Acetone
Dianions
................. .......... .....................
INTRODUCTION
111
RESULTS AND DISCUSSION ...................
EXPERIMENTAL SECTION .........................................................
14
62
General comments ................................
Vapor pressure osmometry ............................
X-ray crystallography ...................
62
63
65
Preparation of 1,1-diphenylacetone dianion [Ph2CC(O)CH21 2 -
(TW-I-72, II-6)..................................
77
Preparation of acetone dianion [CH2C(O)CH2]- 2 (TW-II-28) ........................ 77
I
I
Preparation of Cp2 ZrCH2 C(=CPh 2)0, 7 (TW-II-16, 20, 30, III-49).............. 77
I
I
Preparation of Cp 2 Hf CH 2C(=CPh 2)0, 8 (TW-IV-5, 38, 42) ..................... 80
Preparation of (CpMe) 2ZrCH2 C(=CPh 2)0, 9 (TW-IV-27, 29, 34) ..........
83
1~~~
~I
Preparation of Cp 2 ZrCH 2C(=CH 2)0, 10 (TW-II-33, IV-4, V-4) ................. 85
Preparation of Cp 2Hf CH 2C(=CH 2)0, 11 (TW-IV-40, V- 13) ..................... 88
I
I
Preparation of (PPh 3 )2 PtCHC(=O)CH 2, 17 (TW-IV-61, 65, 70)................. 90
1
I
Reaction of Cp2 ZrCH2C(=CPh 2)0, 7 with HCI (TW-VI-10) ..................... 91
Attempted reaction of l,l-diphenylacetone dianin [Ph2CC()CH21 2 with Cp2TiC12 (TW-III-43, IV-13 .......................................................
92
Attempted reaction of 1,1-diphenylacetone dianin [Ph 2 CC(O)CH 2 ] 2 -
with Cp*2ZrC12 (TW-II-43,
52) .................................
94
6
I
I
Attempted reactionof Cp2 ZrCH2C(=CPh 2)0, 7 with CO (TW-V-46) ............. 94
I
I
Attempted reaction of Cp 2 ZrCH 2 C(-CPh 2)0, 7 with (O=CH2 )n
(TW-V-48)
.................................................
94
I !
Attempted reactionof Cp2 ZrCH2C(=CPh 2)0, 7 with O=CHPh
(TW-IV-11,
31) .................................................
96
Attemptedreaction of Cp 2 ZrCH2C(=CPh 2)0, 7 with HC-=CPh
(TW-III-22,
40)............................................................................
I
96
I
Attempted reaction of Cp 2 ZrCH2C(=CPh 2)0, 7 with t-BuNC
(TW -IV -6) ...................................................................................
I
97
I
Attempted reaction of Cp 2 ZrCH 2C(=CPh 2)0, 7 with Et-NC
(TW-V-45)
............................... ........................
I
97
I
Mass spectra of Cp2TiCH 2C(=CPh 2)0,1 5 ...........................................
REFERENCES ............................................................................
Chapter Two.
97
102
Reactions of Organosilicon Halides with the Ambident 1,1Diphenylacetone Dianion
INTRODUCTION..........
.......
........................108..........
108
RESULTS AND DISCUSSION .......................................................
EXPERIMENTAL SECTION ......................................................
General comments ........................................................................
Vapor pressure osmometry ......................................................
X-ray crystallography ....................................................................
110
164
164
166
168
7
Structure of 1,1,5,5-tetraphenyl-3,7-bis(diphenylmethylene)
-1,5-disila-2,8-dioxacycloocetane,
8 ..................................................
168
Structure of 1,1,5,5-tetraphenyl-3,7-bis(diphenylmethylene)
-1,5-disila-2,6-dioxacycloocetane,
10................................................. 175
Structure of 1,1,2,2,6,6,7,7-octamethyl-4,9-bis(diphenylmethylene)
-1,2,6,7-tetrasila-3,10-dioxacyclodecane, 11......................................... 182
Preparation of 1,1-diphenylacetonedianion [Ph2 CC(O)CH2]2 -
(TW-I-72,
II-6) ...................................................
188
Preparation of 1,1,5,5-tetramethyl-3,7-bis(diphenylmethylene)
-1,5-disila-2,8-dioxacycloocetane,
5 (TW-II- 13,
III-69, 71) ....................... 188
Preparation of 1,1,5,5-tetraethyl-3,7-bis(diphenylmethylene)
-1,5-disila-2,8-dioxacycloocetane, 6 (TW-III-67, 75)............................... 191
Preparation of 1,5-dihydrido-1,5-dimethyl-3,7-bis(diphenylmethylene)
-1,5-disila-2,8-dioxacycloocetane, 7 (TW-III-66, 68)............................... 192
Preparation of 1,1,5,5-tetraphenyl-3,7-bis(diphenylmethylene)
-1,5-disila-2,8-dioxacycloocetane, 8 (TW-IV-30, V-50)............................ 193
Preparation of 1,1,5,5-tetraethyl-3,7-bis(diphenylmethylene)
-1,5-disila-2,8-dioxacycloocetane, 9 (TW-V-3, VI-12) ............................. 195
Preparation of 1,1,5,5-tetraphenyl-3,7-bis(diphenylmethylene)
-1,5-disila-2,6-dioxacycloocetane, 10 (TW-IV- 17, 22)............................. 196
Preparation of 1,1,2,2,6,6,7,7-octamethyl-4,9-bis(diphenylmethylene)
-1,2,6,7-tetrasila-3,10-dioxacyclodecane, 11 (TW-I-48, 50, 52, IV-7)......... 197
Preparation of 1,1,2,2,3,3-hexamethyl-5-diphenylmethylene
-1,2,3-trisila-4-oxacyclohexane, 12 (TW-III-56, 61, 70, IV-10) ................. 199
Preparation of Ph2 CHC(O)CH2SiMe2CH2C(=O)CHPh2,13
(TW-III-72) ..................................................
200
Preparation of Ph2 CHC(=CH2)OSiMe2SiMe2OC(--CH2)CHPh2,14
(TW-III-58, 64, 73)...................................................
201
Preparation of Ph2C=C(CH3)OSiMe3, 17a (PL) .................................... 202
Preparation of Ph2 C=C(CH 3)OSiMe2t-Bu, 17b (PL)............................... 203
Preparation of CH2=C(OSiMe3)CHPh2, 18 (PL).................................... 204
Preparation of Ph2C=C(CH2SiMe3)OSiMe3, 19 (TW-IV-72) .....................
Preparation of Ph2 C=C(CH2SiMe2H)OSiMe2H, 20 (PL)..........................
Preparation of Ph2 C=C(CH2SiMe3)OSiMe2t-Bu, 21 (PL).........................
Preparation of Ph2C=C(CH2SiMe3)OSiPh2Me, 22 (PL)...........................
Preparation of Ph2 C=C(CH2SiMe3)OSiMe2H, 23 (PL)............................
205
206
207
208
209
8
Preparation of Ph2C=C(CH2SiMe2H)OSiMe2t-Bu, 24 (PL)....................... 210
Preparation of Ph2C=C(CH2SiMe2t-Bu)OSiMe2H, 25 (PL)....................... 211
Preparation of Ph2CHC(=O)CH 2 SiMe3, 26 (TW-IV-51) ........................... 212
Reaction of Ph2C=C(CH3)OSiMe3 , 17a with LDA and quenching
with HCISiMe2 (PL) .....................................................
213
Attempted hydrolysis of Ph2C=C(CH2SiMe3)0SiMe3 , 19.
(TW -IV-73) .....................................................
214
Preparation of Acetone Dianion [CH2C(O)CH2]2 - (2) (TW-II-28) ................214
Attempted reaction of acetone dianion [CH2C(O)CH2] 2 - (2)
with Me2SiCl2 (TW-III-45) .............................................................
REFERENCES
...............................
Chapter Three.
215
216
Reactions of Diphenylgermanium Dihalides with the
Ambident 1,1-Diphenylacetone Dianion
INTRODUCTION ............................................................................ 219
RESULTS AND DISCUSSION.........
........................................... 222
EXPERIMENTAL SECTION .....................................................
235
General comments .....................................................
Vapor pressure osmometry .....................................................
X-ray crystallography .....................................................
235
236
238
Prearation of diphenyldifluorogermane (TW-V-18, 19)............................. 246
Preparation of 1,1-diphenylacetone dianion [Ph2CC(O)CH2]
(TW-I-72, II-6) ....................
2-
.................................
246
Preparation of 1,1,5,5-tetraphenyl-3,7-bis(diphenylmethylene)
-1,5-digerma-2,6-dioxacyclooctane,
7 (TW-V-5, 26, 27).......................... 247
Reaction of 1,-diphenylacetone dianion [Ph2CC(O)CH2]2 - with
diphenyldifluorogermane
(TW-V-23, 24) ............................................
REFERENCES.........
249
.................................. 251.........
251
Chapter Four. Synthesis and Characterization of 1,1'-q5 Bis(dimethylvinylsilylcyclopentadienyl)
Group 4 metal Dichlorides
INTRODUCTION ..............................................................................254
RESULTS AND DISCUSSION....................................................
257
9
Preparation and characterization of l,l'-bis(dimethylvinylsilyl)metallocene
dichlorides,
[(fl5 -C
(IV)
5H4SiMe2CH=CH2) 2 MC1 2 ]
( M = Ti, 1, Zr, 2, Hf,3) ................................................................
Preparation and characterization of o-bis(dimethylvinylsilyl)benzene,
257
o-
(CH2=CHSiMe2)2C 6 H4], 4.............................................................
263
Preparation and characterization of 1,l'-bis(dimethylvinylsilyl)ferrocene,
[(rl 5 -CsH4SiMe2CH=CH2)2Fe],
5...
........
............................
268
EXPERIMENTAL SECTION......................................................
General comments .......................................................
272
272
Preparation of dimethylvinylsilylcyclopentadiene,C5H4SiMe2CH=CH2
(TW-I-66).. ................................................................................
273
Preparation of lithium dimethylvinylsilylcyclopentadienide (TW-I-68)............273
Preparation of 1,l'-bis(dimethylvinylcyclopentadienyl)titanocene
dichlorides, 1 (TW-I-40) .................................................
274
Preparation of 1,1'-bis(dimethylvinylcyclopentadienyl)zirconocene
dichlorides, 2 (TW-I-69) .................................................
275
Preparation of 1,1'-bis(dimethylvinylcyclopentadienyl)hafnocene
dichlorides, 3 (TW-I-74) ................................................................
276
Preparation of o-bis(dimethylvinylsilyl)benzene,4
(TW-I-26, 33, TW-V-28) ...............................................................
277
Preparation of 1,1'-bis(dimethylvinylsilyl)ferrocene, 5
(TW-I- 17,
29, 31, 32) ...................................................................
279
REFERENCES ............................................................
281
ACKNOWLEDGEMENTS
283
.
......................................................
10
CHAPTER ONE
Reactions of Group 4 Metallocene Dichlorides with Acetone Dianions
11
INTRODUCTION
A great variety of trimethylenemethanecomplexes of transition metals are known,
especially since such species are postulated as reactive intermediates in metal-catalyzed
syntheses of cyclopentane ring systems.1 One of the main routes to prepare
trimethylenemethane complexes is by using the trimethylenemethane dianion (TMM2-)
1 as
a ligand source. 2 As shown in Scheme 1, The reaction of trimethylenemethane dianion,
2CH 2
H2n
'CH2
1
a 6 n-electron donor, with metal dihalides gives either metallacyclobutanes
or trimethylenemethane complexes, depending on the metal halide and its ligands.
Scheme
1
2-
CH2
-14
I. I .m
H 2 C'
'CH
+
MLnX2
2
LnM
1
Surprisingly, the ready availability of the similar dianion of
oxatrimethylenemethane (OTMM- 2 ) 2 has rarely been exploited as a ligand source for the
synthesis of trimethylenemethane complex analogs, oxatrimethylenemethane complexes.3
12
Oxatrimethylenemethane complexes are known to exist in a variety of coordination modes,
which have attracted much attention both in structural organometallic chemistry and in
synthetic organometallic chemistry. 4
_,
L'
0I
R2
R2'
C
'CR
2
Double deprotonation of acetone and appropriately substituted
acetones results in formation of delocalized dianions of type 2.5 A 1H NMR investigation
of the dilithium salt of the dibenzyl ketone-derived dianion showed high negative charges at
the two benzylic C atoms, which indicates that dianion 2 has a typical "Y-conjugated"
system similar to 1.6 Because of this Y-conjugation, it would be expected that dianion 2 as
a ligand will have very interesting coordination modes to metals. Early research showed
that reaction of such dianions with organic substrates usually resulted in C-C bond
formation. 5f
Thus far, the only use of oxatrimethylenemethane dianions as ligand sources was
reported by Kemmitt and coworkers.7 They reported that treatment of the complexes cis[L2 PtCI2] and trans-[L2PdC12] with the dianion derived from dibenzyl ketone,
K2 [PhCHC(O)CHPh], in tetrahydrofuran afforded the q13 -oxatrimethylenemethane
complexes, 3 (alternate description as puckered metallacyclobutan-3-one, 4) (eq. 1).
13
_
_
1~~~~~~~~~~~~~~~L-
0
.
.
II
I I
I
L2 MCI 2 +
PhHC%
2 K+
=
2KCI +
CHPh
(1)
M
3
LorL
0
2
a
Pt
AsPh3
b
c
Pt
Pt
PPh 3
cod
d
Pd
PPh
e
Pd
PEt3
f
Pt
dppe
t3~~
H
3
4
Thus dianions of type 2 in eq. 1 react with electron-rich metal centers as C,Cdinucleophiles. Since dianions of type 2 should be ambident, they could react with
dihalides of oxophilic metals as C,O-dinucleophiles, giving 2-metallaoxa-3methylenecyclobutanes, 5, rather than metallacyclobutanones.
We report here the
successful generation and characterization of such complexes in solution by reaction of
ambident acetone dianions with Group 4 metallocene dichlorides. In addition, we have
found that the four-membered ring metallacycles dimerize when they crystallize from
solution to give "open" eight-membered ring complexes.
LnM
CCRj
5
14
RESULTS AND DISCUSSION
The possibility that dianions of type 2 could react as C, O-dinucleophiles was
examined using Group 4 metallocene dichlorides as substrates since titanium, zirconium
and hafnium are strongly oxophilic. In our initial experiment the dianion from 1, 3diphenyl-2-propanone, which Kemmitt used for the synthesis of 3-metallacyclobutanones
(eq. 1)7 was allowed to react with zirconocene dichloride in THF solution. As shown in
eq. 2, the expected structure of the product of the [PhCHC(O)CHPh]2-/(15-C 5 H5 )2 ZrCI2
reaction would be the 2-zirconaoxa-3-bis(diphenylmethylene)cyclobutane.
However, no
n
(Tj5 -C5H) 2 ZrCl2 +
eA e
i
IN (T 5-C 5H5)
PhCH iCHPh
(2)
clean product could be isolated. The reason for the failure of this reaction to proceed as
originally envisioned could be due to an unfavorable steric interaction between the Cp
ligands and the Ph groups in the dianion. To avoid this problem, two acetone dianions
with less sterically demanding substituentswere chosen to react with group 4 metallocene
dichlorides: 1, 1-diphenyl-2-propanone dianion, 6a, and acetone dianion, 6b.
Dianions 6a-b have been reported previously in the literature.5 c, 5e A THF
solution of 1,-diphenylacetone (6a) (or acetone, 6b) was added slowly to one equivalent
of KH in THF. After stirring at room temperature for 15-20 min, an orange (6a) (yellow,
6b) solution was obtained. To this orange solution at 0°C, one molar equivalent of nbutyllithium was added (in the case of acetone, 6b, one molar equivalent of nBuLiTMEDA was added). Dianions 6a-b were obtained after stirring the resulting red
(6a) or yellow (6b) mixture for 5-7 min at 0°C.
15
A THF solution of the red dianion 6a was added slowly to one equivalent of
(CpR') 2 MC1 2 (7, R' = H, M = Zr, 8, R'= H, M = Hf, 9, R' = Me, M = Zr) in THF
solution under N2 at -78 °C (eq. 3). The resulting mixture was allowed to warm slowly to
room temperature and was stirred overnight. The resulting orange suspension was
evaporated at reduced pressure. The residue was extracted with toluene. Filtration through
Celite was followed by concentration of the orange filtrate. The concentrated orange filtrate
was added to hexane. The resulting yellow precipitate was washed twice with hexane and
dried in vacuo. Complexes 7, 8 and 9 were isolated in 30-60% yield as yellow solids.
Complexes 10 and 11 were isolated as off-white solids in 48-50% yield by treatment of
dianion 6b in ether with a THF solution of Cp2 MC12 (10 M = Zr, 11 M = Hf) under N2 at
-78°C (eq. 3).
0
O: ® THF
(T-C 5 H4 R) 2 MC 2
+
R2C°C
'CHH 2
6a R=Ph
6b R=H
-780(
-C
/
-
(T15 -CsH4 R')2 M f
C
CR 2
7 M = Zr, R'= H, R = Ph
8 M=Hf,R'=H,R=Ph
9 M=Zr, R'=Me,R=Ph
10M=Zr, R'=H, R=H
11 M=HfR'=H, R=H
Complexes 7-9 were recrystallized from methylene chloride/hexane or
toluene/hexane solution. Complexes 10-11 were recrystallized from toluene or methylene
chloride solution. Complexes 7-11 are moderately air-sensitive and stable in the solid state
under an inert atmosphere. The solubilities of 7-11 are quite different. Complexes 7-9
are soluble in chlorinated solvents, benzene, toluene, diethyl ether, and THF. Complexes
10 and 11 have very low solubilies in chlorinated solvents, benzene, toluene and ethereal
solvents. The physical properties of 7-11 are given in Table 1.
(3)
16
Table 1. Physical properties of 7-11
compound yield
mpa
analysis: % calculated/found
7
8
%
58
50
(°C)
185-187
215-218
C
64.85/64.56
58.08/58.19
H
4.92/4.91
4.30/4.35
9
30
161-164b
70.84/69.25
5.74/5.75
10
11
50
48
150-153
199-201
56.27/56.05
42.81/40.99
5.10/5.11
3.87/3.51
a. dec. b. there is 5-10% impurity in this sample
Complexes 7-11 were fully characterized by 1 H and
13 C
NMR spectroscopy,
variable-temperature 1 H NMR spectroscopy, IR spectroscopy, mass spectroscopy,
elemental analysis and vapor pressure osmometry. The solid state structure of 7 was
determined by an X-ray diffraction study.
The 1 H NMR spectral data for 7-11 at 250 C are given in Table 2. In the 1 H NMR
spectra of 7, 8 and 9 (Figure 1-3), 7 and 9 exhibit single broad resonances for the
CH2 - groups, while the 1H NMR spectrum of 8 shows two broad resonances for the CH2
group. Two broad resonances were observed for both cyclopentadienyl rings for 7 and 8,
and four broad resonances were observed for both cyclopentadienyl rings of 9. Attempts
to isolate an analytically pure sample of 9 have not been successful. The product contains
approximately 5-10% of an impurity which could not be removed by repeated
recrystallizations using various solvents. This impurity is easily detected by 1H NMR
spectroscopy but could not be identified. A resonance appears at 5.5 ppm in the 1H NMR
spectrum which is not temperature dependent. In contrast to 7, 8 and 9, the 1H NMR
spectra of complexes 10 (Figure 4) and 11 (Figure 5) at room temperature exhibit only
one signal for the cyclopentadienyl rings and one signal for the zirconium-methylene
protons. The two vinyl protons resonances are observed as two singlets.
17
The
13 C
NMR spectral data for 7.11 are given in Table 3. The data are consistent
with the results from the 1 H NMR spectra. All the compounds show characteristic triplet
resonances for the -CH2 - carbons. No carbonyl carbon peaks are observed. This provides
clear evidence that dianions 6a and 6b react with zirconocene and -hafnocene dichlorides
as C, O- dinucleophiles.
18
..
la
-M
CO
0
in
t-
N
-To
!ex
M
Sm
19
o
o00
m
u
Q
0
In
0
c
o
LO
aC.
*Q
0
(
1r
20
I-
0
CN
VW
o
10
-N
-0
E(4
0
0
o
i
P0
Z
u
eE
-
-
S.
o
.
21
i
K
I
I
I
i
-cJ
V
_n
en
~o
qV
N
-IT
-t
co
a
Pi
._
A
C
m
Im
22
I
a
.o
Q
Cu
U
O
0N
u
11
e..
uadU,
s
0
0
(n
-
i
z
23
Table 2.
1H
NMR spectra data for 7-11
Compounds (ppm)
7
8
9
10
11
1.81
Mult
br s
J (Hz)
Area
Assignment
2
CH 2
5.51
6.00
br s
5
C5 H 5
br s
5
C 5 H2
7.10-7.70
m
10
Ph
1.54
1
CHaHb
1.70
br s
br s
1
5.50
br s
5
CHaHb
C 5H 5
5.95
br s
5
C 5H 5
7.05-7.58
m
10
Ph
1.70
br d
6
CH 3
1.84
br s
2
CH 2
5.49
br d
5
C5 H 5
6.10
br d
5
C5 H 5
7.10-7.60
m
10
Ph
1.61
s
2
CH 2
3.69
s
1
C--CHaHb
3.84
s
1
C=CHaHb
5.76
S
10
C5 H 5
1.37
S
2
CH 2
3.72
S
1
C=CHaHb
3.74
s
1
C=CHaHb
5.80
s
10
C5 H 5
24
Table 3.
13 C
Compound
7
8
9
NMR data for 7-11
6 (ppm)
46.9
Mult
J (Hz)
Assignment
t
121
CH 2
108.2
s
111.1
d
124.0-145.1
m
170.1
t
5 (2 J)
Ph
CH2 C=CPh2
48.3
t
120
CH 2
110.1
s
110.5
d
124.6-145.6
m
170.1
t
5 ( 2 J)
CH2 C=CPh2
14.7
q
125
CH 3
48.9
108.2
111.6-115.6
t
122
CH 2
11
C5 H 5
C=CPh2
171
C 5 H5
Ph
s
C=CPh2
m
C5 H4 Me
Ph
171.6
m
s
32.9
t
131
CH 2
79.4
t
158
C=CH2
109.9
d
178
172.0
C 5H 5
t
(2 J)
48.2
t
120
CH 2
79.5
t
158
C=CH2
110.6
d
178
C5 H 5
t
( 2 J)
CH2 C=CH 2
124.2-146.1
10
C=CPh2
175
176.2
CH2 C=CPh2
6
4
CH2 C=CH 2
25
The broad resonances for the methylene and cyclopentadienyl protons are likely to
be caused by the dynamic process of rapid ring inversion. To examine this, the solution
structures of 7-11 were studied using temperature dependent 1 H NMR spectroscopic
techniques. Spectra taken at selected temperatures for complex 7 are shown in Figure 69. At room temperature two broad resonances are observed for both cyclopentadienyl
rings. The zirconocene methylene protons appear as a broad resonance. Decreasing the
monitoring temperature results in splitting of the methylene signals as well as of the l15cyclopentadienyl resonances. At the limiting low-temperature, -17 °C, the methylene
protons are resolved into two doublets which show a typical AB pattern, and the two broad
cyclopentadienyl signals are resolved into two singlets. At 50 °C, the cyclopentadienyl ring
signals coalesce into a single peak, reaching the fast-exchange limit at 90 °C. These results
suggest that the structure of 7 in solution is a puckered 4-membered ring as shown in
Scheme 2. Some oxotrimethylenemethanepalladium and platinum complexes undergo
Scheme 2
SCPh2
_
,,
CPh2
1
H
ring inversion in solution, as evidenced by their temperature-dependent
1H
NMR spectra (Scheme 3). The experimental activation energies for this process lie
between 8.4 and 12.2 kcal/mol. 3 8
26
-cu
a/
0
o
rI
r
-0Z
U,
Ls
*a
-on
Eu
L,
13
wwI
i
27
-I
-c
@0
5
I1
.0
-m
II
co
t-
I.NZ
-w
mo
28
of
m.
O
IIo
v
0
o
29
I-r
0a.t
a/
V
mc
Qa
Si
Q
0
t'IV
o
rA
rV
Al
uU11
I5i
V
u
$4
e4
cu
Q
I
q*"
b9tjz
P1
hi
Cy;
Lfi
30
Scheme 3
L
&0
Lo
L
:!:
*
C"
II
The free energy of activation of the ring inversion can easily be
calculated from the chemical shift difference of the Cp resonances observed at the slow
exchange limit of the variable temperature 1H NMR spectra and the coalescence temperature
T(Cp). 9 At the coalescence temperature, the rate constant for exchange can be obtained
from the following equation:
k=
7
(6a-
)
2
where
Sa
is the chemical shift (in Hz) of one Cp and 8 b is the chemical shift of another Cp
at the slow exchange limit.
For 7, the two resonances are separated by 0.51 ppm at the slow exchange limit and at 300
MHz:
A = 6.07-5.56 = 0.51 ppm (300 MHz) = 153 Hz
and thus, at the coalescence temperature (50°C):
k r (AS)
42
i
(153
) =340
42
The Eyring equation gives the relationship of the rate constant to AG:
31
k = (icT/h) e-AG/RT
thus,
AG = -RT[ln (kT) + In (h/ic)]
where
R = 1.987 x 10-3 kcal/mol-K
c = Boltzmann's constant = 1.38054 x 10-16 erg/k
h = Planck's constant = 6.6256 x 10-27erg-sec
T = temperature in K
thus, for complex 7
AG = 15.3 kcal/mol
This value is rather high for a simple cyclobutane-type ring inversion, but is more
understandable if 7 is present as the r14-oxatrimethylenemethane
process observed in the variable-temperature
1H
complex. In that case, the
NMR experiments would favor an 14-
zirconaoxatrimethylenemethane complex as shown in Scheme 4. The intermediate in
such a process could be a 2-zirconaoxa-3-methylenecyclobutane.
32
Scheme
4
r
Q=z~
I
II
I
A
%-112
-.'
-U
A
Ph2C--C.
g
' u-
I
r8~ZY,
J
'V1W
VI
An analogous process reported by Erker and coworkers shows very similar
dynamic spectroscopic features for (s-cis-diene) zirconocene and hafnocene complexes, in
which the bent metallocene unit migrates from one face of the diene ligand to the other by
proceeding through five-membered metallacyclic structures (Scheme 5). 10 The activation
barrier of this characteristic automerization process for (s-cis-conjugated diene) zirconocene
and hafnocene complexes has proved to be very dependent on the structure and substituents
of the diene ligand. The highest known activation energy was observed for
tetramethylbis(methylene) tricyclo[3.1.0.0] hexane zirconocene complex (AG = 14.3
kcal/mol).
33
Scheme 5
IR.,
RA
.- Y
-of
D
N2
Vt
I&
D
I
R21
I
In another example, Hartwig and Bergman11 reported that thermolysis of the
enolate complex [RuMe(OC(=CH2)Me)(PMe3)4]
afforded both the metallacyclobutan-3-
4 -oxatrimethylenemethane complex, 13 (Scheme 6). The
one complex, 12, and the TI
interconversion of complexes 12 and 13 is reversible.
34
Scheme 6
VRu
L
LRu
4
-CH4
+
12
600, 6h
+L
-L
L4Ru
,L=P
L= PMe3
L
13
The question as to whether the ring inversion is an intramolecular process or an
intermolecular process was addressed by changing the sample concentrations in the
variable temperature
1H
NMR experiments. If the ring inversion is an intermolecular
process, different coalescence temperatures would be observed with different sample
concentrations. 9 The variable temperature 1H NMR spectra at the coalescence temperature
for three different concentrations of 7 (8 mg/mL, 12 mg/mL, 16 mg/mL, toluene-d8 as
solvent) are shown in Figures 10-12. The same coalescence temperature of 500C was
observed in each case. This indicates that the inversion rate is independent of
concentration, i.e., that the ring inversion is an intramolecular process.
35
toluene-ds
T = 50°C
f I
. .i
..
' I0
..
I
.
-.
.I Iii 0r
.. rrr
o7.0
60
'5o
T = 25°C
0
70
L
A
-
S.!
....
a
0a ....
.. .. . . . . . . . . .
4.0
A-
Am
Tl-r-rrrr I
30
ao
_
o
toluene-ds
... 3.
0. .
J~~~~~o
.
.
.
.
.
.
Figure 10. VT 1H NMR spectrum of Cp 2 ZrCH 2 C(=CPh 2 )O, 7
at a concentration of 8 mg/mL
......
.~~~~~~2,6
I
o
36
*,Jluuan..A..
A~A
.a
a
.
. ' .,..
I0.
7'a
I,,,I
61
0
,I .
V.
.
I.
0.04.0
S.Ia
.
3I
.
aa
I . ..
....'
...
-- I
30
T=25' "
toluene-ds
_
.
4.0
30
A
.I
12
Figure 11. VT 1H NMR spectrum of Cp2 ZrCH2 C(-CPh 2)0, 7
at a concentration of 12 mglmL
.
-
-
' - I
I . 1
1 O
37
T = 50°C
toluene-ds
0
.
.
6.0
0
50
I
I
.0
I
. 20
30
10
T= 25°C
toluene-ds
.
.
30~~rrri7T"71~~~~~~
6.0
I .
.
..
-I--'-,..£
*a
AdI0 .
.
. . .4.0I
. . .
20
30
I
l
Figure 12. VT 'H NMR spectrum of Cp2ZrCH 2C(=CPh2)0, 7
at a concentrationof 16mghnL
t
u
38
Similar dynamic 1 H NMR spectra were obtained for 8. Again, two broad Cp
resonances were observed at room temperature, which split into two separate sets of Cp
signals of equal intensity on lowering the temperature to 13°C. The Cp resonances
coalesced into a single peak at 45°C, reaching the fast-exchange limit at 90°C. In contrast to
complex 7, two broad resonances were observed for the hafnocene methylene protons at
room temperature, which were split into two doublets (AB pattern) at 130 C. The free
energy of activation for the ring inversion indicated by these results is estimated to be 15.0
kcal/mol.
The temperature dependent 1H NMR spectra of complex 9 also were obtained. The
free activation energy for ring inversion was estimated to be 15.6 kcal/mol. Complete
variable temperature
1H
NMR spectral data are provided in the experimental section.
The 1 H NMR spectra of complexes 10 and 11 also are temperature-dependent.
Spectra taken at selected temperatures for complex 11 are shown in Figure 13-16. At
- 78.5C the cyclopentadienyl signal resolved into two singlets (AS = 51 Hz) and the
methylene resonances also appeared as two broad doublets. The cyclopentadienyl signals
coalesced into a broad peak at -58.50C. The free energy of activation for this process was
calculated by the Eyring equation to be 10.4 kcal/mol. In the VT 1 H NMR spectra of 10,
the cyclopentadienyl resonances appeared as two singlets (AS = 3 Hz) at -700C and
coalesced into a single peak at -570C. The methylene signal also resolved into two doublets
(AS = 45 Hz) at -70°C with a coupling constant of 10 Hz. The free energy of activation,
AG, was calculated to be 11.7 kcal/mol.
39
W.
a
-0
o
Vr
Q
_o
-0
co
-0
0
0II
U
1-1
i
EM
11
ru
Z
em
13
9
lbi
_n
0
I.
U
0
tto
0
-La
40
-0
U
0
o
0
-cu
0
II/
1
Q
II
u
3
0
-Io
tm4
In
4b
m
0
- m o
o
lb
I
u
..m
41
x
0.
o
0
a.
o
II
/1
go
la
0
0
0
4ro
I4
3
0
en
-m
Wi
0
t
- po
i
z
42
-a
a
U
0
In
co
r-4
go/
-0
IL
-r M
U
_ X
I;
U
i
'U.
-o
C-)
Ea
w
0
Ue1
0
*_
co
W
09
·I
-0o
CD(
43
The solution structure of these complexes also was supported by vapor pressure
osmometry. A determination of molecular weights for 7 and 8 by VPO in chloroform
solution gave 410 and 499, respectively. These are, within experimental error (< 10%),
the molecular weights of the four-membered ring compounds. The low solubility of 10
and 11 in chloroform, benzene and toluene prevented us from obtaining molecular weight
data for these complexes. The molecular weight of 9 in solution is not available due to the
presence of an impurity. The VPO data for 7 and 8 are given in Table 5.
Table 5. VPO data for 7 and 8
compound
VPO: calculated/found
7 (C25H22ZrO)
429/410
8 (C2 5 H22HfO)
517/499
The solution structures of 7-11 can readily be compared to those of the
titanaoxacyclobutanes reported earlier by Grubbs and coworkers,1 2 who used different
preparative routes (eq. 4 and eq. 5). Monomeric structures in solution were indicated for
14 and 15 on the basis of cryoscopic molecular weight measurements and their 1H NMR
spectra. In particular, a VT 1H NMR study of 14 and 15 gave results similar to those
obtained with our zirconium and hafnium analogs 7-11, which showed that the
metallaoxacyclobutane rings were puckered with a barrier to inversion of 13 kcal/mol for
14 and 19 kcal/mol for 15. Our attempts to prepare the titanaoxacyclobutanes
15 by the
reaction of dianion 6a with Cp2TiCl2 and Cp2Ti(OTf)2were unsuccessful. The 1H NMR
spectra of the crude products indicated the presence of the expected 2-
titanaoxacyclobutanes, but the presence of impurities in large amounts prevented their
isolation.
44
CH 3
I
0
II
(15-CSH
5)2Ti \
+
2 CH 2S(CH3 ) 2
C1
-
J~
+ (CH3 )2 S
(5-CH2Ti
\ 2C-H
(4)
+ (CH3) 3 j
H2
C
14
H2
(T5-C5H5)2Ti /
C\
CHt-
+
Ph 2 C-=C=O
1
C
H2
CPh2
(n15 -C5H) 2 Ti
+
t-BuCH=CH2
(5)
15
By comparison of the free activation energies of 7, 8, 10, and 11, and of 14 and
15 reported by Grubbs, it is apparent that the ring inversion activation barrier of
metallaoxacyclobutanes is dependent on the substituents (R) of the dianion ligand. A
higher free energy of activation for ring inversion was observed for the 1,1diphenylacetone dianion-derived complexes than for the acetone dianion-derived
complexes. Another notable difference is that the free activation energies, AG, for the
hafnium complexes 8 and 11, are lower compared to those of the zirconium analogs 7 and
10, which also are lower than those of the titanium analogs 14 and 15, as reported by
Grubbs. Erker observed the same notable differences between corresponding pairs of (s-
45
cis-r -conjugated diene )zirconocene and -hafnocene complexes.
10
b He suggested that the
hafnium complexes exhibit a higher degree of o-complex character (metal alkyl character)
than their zirconium counterparts. Based on this suggestion, it would be expected that
zirconium complexes 7 and 10 are more like
4-oxatrimethylenemethane
complexes than
are the hafnium analogs. The free activation energies of 7, 8, 10, 11 and 14, 15 are
listed in Table 4.
Table 4: The free activation energy of ring inversion for 7, 8, 10, 11, 14 and 15
compound
dianion ligand
AG
M
ref
19
Ti
11
15
1,1-diphenylacetone
7
1,1-diphenylacetone
15.3
Zr
this work
8
1,1-diphenylacetone
15.0
Hf
this work
14
acetone
13
Ti
11
10
acetone
11
acetone
11.7
10.4
Zr
Hf
this work
this work
The thermal stability of 7-11 is of interest. 2-Metallaoxacyclobutane complexes
often are invoked as intermediates in transition metal catalyzed olefin epoxidation
reactions. 1 3 Only recently, several stable early transition metal metallaoxacyclobutanes
have been reported. 1 4 It is known that these metallaoxacyclobutanes decompose smoothly
when heated to generate an olefin and the corresponding metal oxide. Bazan and
I
I
Schrockl4a showed that trans- Mo[CH(t-Bu)CH(C 6F)O](NAr)(O-t-Bu)
2
decomposes
easily to trans C6 F5 CH=CH(t-Bu) and the corresponding molybdenum oxide complex (eq.
mbI
I
6). Bercaw and coworkersl4b showed that O-ant -Cp* 2(CH 3 )TaOCHRCH
to give CH 2 =CHR and the tantalum oxide complex (eq. 7).
2
decomposes
46
Ar
N
H
Mo(O)(NAr)(O-t-Bu)
2
t-BuO%"'Mo
(6)
t-BuO
C6FsCH = CH(t-Bu)
| wt-Bu
H
/ CH3
50-130 0 C
+
CH= CHR
(7)
Unlike the molybdenum and tantalum analogs, 7-11 are quite thermally stable in
solution. Compounds 7-11 can be heated to 1000 C in toluene solution overnight without
decomposition (eq. 8). The titanium analog also showed such unusual stability.1 2 It has
been proposed that the unusual stability of titanaoxacyclobutanes is due to the puckering of
the ring to increase bonding by donation of the oxygen lone pair electrons to the titanium
center and to the absence of steric crowding at the planar sp2 0-carbon. 1 2 In addition to the
reasons proposed above, we added another two reasons for this unusual stability - the
nature of the olefin (an allene) that is generated when a metallacycle cleaves to give
"(Cp2M=O)n", and the absence of steric crowding at the a-carbon.
Cp2 M\1CR
M = Zr, Hf
R = Ph, H
2
-
- H2C=C=CR2 + (Cp2M=O)n
(8)
47
It was expected that 7-11 might undergo insertion reactions to form larger rings.
1-Sila-3-zirconacyclobutane
16 has been known to undergo insertion of (O=CH 2) x to form
large ring complexes (eq. 9).15 Complexes 7-11, however, were completely inert
Me 2
Cp2Zr
Si\
+ (O= CH
2)n
C
r(9)
16
towards insertion of CO, (O=CH2)x, PhHC=O, HC-CPh, and CN-R (R = tBu, Et)
(see Experimental Section). Even at 1000 C, compound 7 proved to be inert towards the
insertion of tert-butylisocyanide.
The difference in reactivity between 7 and 16 probably is
caused by the reduced oxophilicity of the Zr atom in 7 due to the g-donation from oxygen
to the electron-deficient metal center. It was proposed that the insertion of (O=CH2)n to 16
was initiated by electron-pair donation of a lone pair from the O into the dz2-like LUMO of
the d o Zr (IV) center.
The reaction of 7 with anhydrous HC1yielded zirconocene dichloride and 1,1diphenyl-2-propanone (eq. 10).
/0\Ph
Cp 2Zr /
C=C\
C
H2
+
Ph
HCl
C 6D 6
C
II
Cp2 ZrCl2 +
1l
Ph 2CH
(10)
CH 3
3
48
The above study has shown that [CH2C(O)CR2]2- (R = Ph, H) dianions react with
oxophilic bis (cyclopentadienyl) dichlorides of zirconium and hafnium as C, O
dinucleophiles, giving 2-metallaoxacyclobutanes in solution. To demonstrate that
[CH2C(O)CR2] 2 - (R = Ph, H) are indeed ambident in their reaction with metal dihalides,
they were allowed to react with (Ph3P)2PtCI2. The reaction of [CH2C(O)CPh2 ] 2- dianion
with (Ph3 P)2PtCI2in THF at -780 C gave an orange solution. The THF was removed and
the residue was extracted with toluene. Filtration under nitrogen through Celite gave a clear
yellow solution, which quickly turned black after standing at room temperature for a few
minutes. A gray solid was obtained after recrystallization from toluene/hexane. The
3 1p
NMR spectrum indicated that a mixture of several compounds had been formed. Attempts
to recrystallize the mixture from a variety of solvents failed to yield a pure product. It is
apparent that the product of the [CH2C(O)CPh2]2'/(Ph3P)2PtCI2reaction decomposed.
However, the reaction of the [CH2C(O)CH2]2- dianion with (Ph3 P)2PtCI2 gave the pure
product 17 in 45% yield (eq. 11), whose spectroscopic properties (IR, 1H, 13C, 3 1 P
NMR) were identical with those reported by Kemmitt for this compound (prepared by
reaction of Me3 SiCH2C(O)CH2CIwith Pt(trans-stilbene)(PPh3)2).8 The product of the
[CH2C(O)CH22-/(Ph3P)2PtCI2reaction, 17, clearly shows that reaction of an acetone
dianion with late transition metal dihalides gives a metallacyclobutanone complex,
demonstrating C,C-dinucleophilic reactivity toward electron rich metal centers.
0
H2
.1. 4
Ph3P\
II
(Ph3P)
2PtC2 + , o,
H2C 'CH
C\
P78Ct
C2
Ph3P
C
H2
17
(11)
49
At this point, the molecular structures for 7-11 in solution had been determined by
VT 1 H NMR spectroscopy and VPO to be monomeric 2-metallaoxacyclobutanes.
The EI
mass spectra of complexes 7-11, however, showed that the highest mass peaks, m/z,
were exactly twice the molecular weight of the monomeric compounds. This would
suggest that 7-11 exist as "dimers", 7'-11', in the solid state. Selected m/z data are given
in Table 6. In the mass spectra of 7', 8', 10' and 11', [8] -4 [4] -
[2] + [2]
decompositions of the eight-membered rings also were observed (Scheme 7). The
presence of M+ peaks for each compound is noteworthy. This indicates that "dimers" can
fragment into "monomeric" form under certain conditions.
Table 6. Selected mass spectrometry data for 7-11
compounds
7' (C50 H44Zr20
calcd. Mol. wt.
2)
856 (90Zr)
M/z (fragment: relative intensity)
856 (2M+; 12)
428 (M+; 100)
236 (Cp2Zr=O, 24)
192 (Ph2C=C=CH2, 50)
8' (C 5 OH44Hf2O2 )
1036
( 1 8 0 Hf)
1036 (2M+; 27)
518 (M+; 70)
326 (Cp2Hf=O, 19)
192 (Ph2C=C=CH2, 35)
9' (C50H52Zr2O2)
912 (90Zr)
912 (2M+; 13)
456 (M+; 100)
10' (C26H28Zr2O2)
552 (Zr)
552 (2M+; 5)
276 (M+; 8)
236 (Cp2Zr=O, 12)
11' (C26H28Zr2O2)
732 ( 1 80Hf)
40 (H2C=C=CH2, 81)
732 (2M+; 4)
366 (M+; 15)
326 (Cp2Hf=O, 30)
40 (H2C=C=CH2, 48)
50
Scheme 7
Cp\
D/Cm CR 2
Cp2MX
C
H2
up
uP
Cp2M--O
+
R 2C
C--
CH2
Two possible dimer structures are shown in Figure 17. One structure,
A, could be described as a dimetallatricyclic compound (a coordination dimer), and the
other, B, is the isomeric eight-membered dimetallamonocyclic structure, an "open" dimer.
R
R-C
R CI
CH2
I
(CpR'M)-O
0-M(CpR')
C
/
R
C
K
H2C-C\
R
A
B
Figure 17. Two possible dimer structures for 7' -11'
In most previously reported examples, zirconaoxacycloalkanes of
ring size < 5 were shown to be of type A in the solid state. Some examples are shown in
Figure
18 (17,16 18,17 19,18 20,19 21,20).
51
R-N
CPh 2
CH 2
CH2
Cp2 Zr
I
Cp2Zr
Cp2 Zr-\
O
OCH 2
Y-
ZrCp2
ZrCP
2
C
I
7 -\
H2 C
N
CPh 2
19
18
Cp2 Zr-
20
0
ZrCp
2
O-
21
Figure 18. Examples of coordination dimers
Ca
22
R
52
Generally, it has been observed that as the metallaoxacyclic ring size decreases, the
tendency for dimerization via Zr 20
2
linkages increases. 2 1 In small ring sizes, The ring
strain would make overlap of an oxygen lone pair with a vacant Zr d orbital less
energetically favorable, resulting in a weaker i interaction between the oxygen lone pair
and the vacant Zr d orbital. By dimerization, the electron deficiency at the metal center can
be decreased. In contrast, the zirconaoxaacycloalkanes of ring size > 7 were shown to
possess monomeric structures, for instance, the metallaoxacycloheptene complexes of
zirconocene which are monomeric in solution and in the solid state. 2 2 In larger ring sizes,
the decreased ring strain would make the Zr-O X interaction more energetically favorable,
resulting in a shortened Zr-O bond, greater electron density at Zr metal center, and
decreased tendency towards dimerization. The electron deficiency at the metal center then
can be decreased by 7r-donationfrom the adjacent oxygen atom as shown in Figure 19.
MQ
Figure 19. n-donation from oxygen with ring sizes > 7
Interestingly,
Erker et al. recently crystallized both structure types of the same
I
I
dinuclear tartratozirconocene complex, [Cp2 ZrOCH(E)CH(E)O]
2
as shown in Figure
20 (E = CO2CHMe2, CO 2 CH 3 ) (i.e. dimetallatricyclic compound type A and isomeric
dimetallamonocyclic compound type B).2 3 It had been suggested that both "coordination"
and "open" dimers are probably very close in energy.
53
I
H
E
H
A
E
B
E = CO 2 CHMe 2 , CO2 CH 3
r
I
Figure 20. Two isomeric structures of [Cp 2ZrOCH(E)CH(E)O] 2
In order to unambiguously determine the solid state structure of our Zr and Hf
complexes, an X-ray diffraction study of 7' was performed by Dr. William M. Davis at the
Single Crystal X-ray Facility, Department of Chemistry, MIT.
Single crystals of X-ray quality were obtained via the slow diffusion of hexane into
a concentrated CH2C12 solution of 7. During the solution of the structure, it was
discovered that a solvent molecule, methylene chloride, had cocrystallized with 7' (see
Experimental Section). Figure 21 shows an ORTEP plot of the molecule. Surprisingly,
it was found that 7' possesses a structure of type B. This is the first example of a
zirconaoxacyclobutane that is monomeric in solution but is dimeric in the solid state.
Furthermore, the dimeric compound exists as an open eight-membered ring as opposed to
the tricyclic coordination dimer usually observed in similar cases. Selected bond distances
and angles are given in the Table 7 and Table 8. Complex 7' adopts a crown
conformation as can be readily seen in the side view plot of 7', shown in Figure 22. The
Zr(1)-O(1) and Zr(2)-0(2) bond distance of 1.956 (3) A is shorter than the value (2.112.14 A) estimated from the sum of the covalent radii for Zr (1.45-1.48 A) and oxygen
54
4 It is comparable to that observed for the six-membered -oxa-4-sila(0.66 A).2
zirconacyclohexane,
Cp 2ZrOCH 2CH2SiMe 2CH 2 (23, 1.941 (2) ,)15 and the seven-
membered zirconacyclic product obtained from coupling reactions of (s-transI
-
I
butadiene)zirconocene with benzophenone, Cp2Zr(OC(C6 H5 )2CH2C(H)-C(H)CH)
(24,
1.946 (4) A), shown in Figure 23.22 The Zr-O bond distances of 7' also are shorter
than those of other dizirconaoxatricyclic compounds (17-21, 2.103 A-2.227 A).16-20
Oh
23
24
Figure 23. Two examples of 2-zirconoxacycloalkanes
One may conclude that there is multiple bond character in the Zr-O bonds in 7' involving
n-donation from the oxygen atom to the empty orbital (al) of zirconium. This n-donation
increases the electron density at the metal center and further stabilizes the complexes. The
bond distances of C(2)-C(3) (1.353 (6) A) and C(5)-C(6) (1.342 (6) A) are typical of C-C
double bonds. 2 5 The distances between Zr(1)-0(2) and Zr(2)-O(1) of 3.435 (3)
A and
3.409 (3) A, respectively, indicate that there are no transannular bonding interactions, thus
eliminating a coordination dimer structure from consideration. The bond angles of Zr(l)0(1)-C(5) and Zr(2)-0(2)-C(2) in complex 7' are 148.2 (3)° and 151.7 (3)0, respectively,
which are quite similar to the bond angles of complexes 23 and 24.
55
Table 7. Selected intramolecular bond distances for 7'
Atom
Atom
Distance
Atom
Atom
Distance
Zr(l)
0(1)
1.954(3)
Zr(2)
0(2)
1.953(3)
Zr(l)
C(1)
C(1)
Zr(2)
C(4)
C(4)
C(5)
2.335(4)
C(2)
2.307(4)
1.483(6)
0(1)
C(S)
1.354(5)
0(2)
C(2)
1.350(5)
C(2)
C(3)
1.349(5)
C(S)
C(6)
1.337(6)
1.450(6)
Table 8. Selected intramolecular bond angles for 7'
Atom
Atom
Atom
Angle
Atom
Atom
Atom
Angle
0(1)
Zr(l)
C(1)
97.5(1)
Zr(1)
0(1)
C(5)
148.2(3)
Zr(2)
0(2)
C(2)
151.7(3)
Zr(l)
C(1)
C(2)
115.6(3)
0(2)
0(1)
C(2)
C(1)
113.1(4)
Zr(2)
C(4)
C(5)
116.6(3)
C(5)
C(4)
111.8(4)
C(10)
C(3)
C(20)
115.3(4)
C(30)
C(6)
C(40)
115.2(4)
C(4)
C(S)
C(6)
129.1(4)
0(2)
0(1)
Zr(2)
C(4)
C(6)
97.1(1)
119.0(4)
C(1)
C(2)
C(2)
C(3)
127.9(4)
C(1)
113.1(4)
C(5)
0(2)
56
~
A
A
45
C41
C62
-32
C31
C61
33
C65
C69
C1
C
7
02
C58
C59
C3
Cll
C12
C53
C15
C
14
C54
C23
I.
cQ11
i
I
Figure 21. ORTEP diagram for [Cp2ZrCH2 C(=CPh2)O], 7'
2
57
o
Lr-
u
"U
cu
C.r
NU
e4
o
0
. i
cu
u
cu
N
58
The interconversion of the four-membered monomeric structure 7 in solution and
the eight-membered "open" dimer 7' in the solid state is reversible. This process can be
easily observed by VPO, and by mass spectroscopy. When the eight-membered ring dimer
7' was dissolved in chloroform, the monomeric four-membered ring, 7, detected by VPO,
always was obtained. The eight-membered ring dimer 7', which was detected by mass
spectroscopy, can be readily obtained by crystallization of 7 from this chloroform solution.
Attempts were made to cocrystallize 7 with donor ligands such as pyridine and
trimethylphosphine in a variety of solvents. The crystallized product isolated, however,
always was the simple dimer which was detected by mass spectroscopy.
In a simple cross-over experiment, a 1:1 mixture of 7' and 8' was dissolved in
toluene. After careful crystallization from toluene at - 23°C, a yellow crystalline solid was
obtained. An El MS spectrum showed, in addition to the mass peaks, m / z, at 856 and
1036 for the parent M+ ions of 7' and 8', a mass peak at 946 of very low intensity, which
possibly could be attributed to the Zr/Hf mixture species, compound 25, as shown in
Figure 23. Unfortunately, the EI mass spectrum of pure 8' also exhibits a mass peak at
946. So this cross-over experiment is inconclusive. The low solubility of 10 and 11
prevented any cross-over experiments with 7' or 8'.
Ph
Ph\
A
C
Ph
C
Hf-CH
Cp/
2
C
Ph
Cp
25
Figure 24. possible structure of a mixed 7' / 8'product
59
A proposed mechanism for this dimerization/dissociationprocess is shown in
Scheme 8. The eight-membered ring, 7', in solution apparently is sufficiently flexible to
allow transannular interactions to give a coordination dimer. The latter then dissociates to
give 7. The driving force for this process could be the entropy increase in solution.
I
I
Finally, why does the 4-membered ring of the kinetic product, Cp 2ZrCH 2C(=CPh2)O,
convert spontaneously to an 8-membered ring "open dimer"? It has been proposed that the
open dimeric structure of [Cp2ZrOCH(E)CH(E)O] 2 (E = C0 2 CHMe 2 , C0 2 CH 3) is
energetically favored due to the formation of two strong Zr-O bonds and large bond angles
at the ring-oxygen centers.2 3 The bonding angles for 7' at the ring-oxygen center are
148.2 (3)0 for Zr(l)-O(l)-C(5),
and 151.7 (3)0 for Zr(2)-0(2)-C(2).
This large bond angle
should provide a very strong interaction between sp-hybridized oxygen and zirconium,
which is necessary for a sufficient energetic competition against the alternative 4-membered
ring monomeric complex 7 in the crystalline state.
Crystals of 14 and 15 suitable for an X-ray structure determination could not be
obtained, so their solid state structures remain unknown. 1 2 Reinvestigation of
titanaoxacylobutanes
15 by EI mass spectral analysis showed a molecular ion peak at 772,
which is consistent with the dimeric species. The highest molecular ion peak, 787, may be
due to the recombination of molecular fragments. The dimeric structure of 15 is further
supported by the FAB mass spectroscopy, which gave a highest molecular ion peak at 774.
This is consistent with M + 2 molecular ion peak for a dimeric species and further supports
that the compounds reported by Grubbs are dimers in the solid state (see Experimental
Section).
60
Scheme 8
Ph
I
PhCp2 Zr/OC
H
I
/Ph
/C\
CH2
I
Cp2 Zr- 0\
Ph
O-- ZrCp2
H
I
I
H2C-
C
7
C-
Ph
I
Ph
I
Cp\
/Cp
,Ph
Ph
=C
Ph
C=
=PC\
O. zr CH2
Cp/
Cp
7'
Ph
61
Our attempts to prepare zirconaoxacyclobutane complexes by reaction of Cp*2ZrC12
(Cp* = T 5- C5 Mes) with dianions 6a and 6b were unsuccessful. Hillhouse and Vaughan
recently reported that by replacing Cp with Cp*, a zirconaoxacyclobutene (Figure 25),
26, instead of 22, a coordination dimer, could be isolated from the reaction of
Cp*2Zr(C2Ph 2 ) with N2 0. 2 6 The sterically demanding pentamethylcyclopentadienyl
ligand
stabilizes many complexes, but it also hinders their reactivity and causes side reactions.
Dianions 6a and 6b are very strong bases due to the presence of alkoxide and carbanion
centers (similar to the n-BuLi / t-BuOK system). A complexity of the resonances at 2.00
ppm in the 1H NMR spectrum likely indicates that the dianions attacked the methyl groups
of the Cp* ligands. A complex product mixture was obtained from the reaction of
Cp*2ZrC12 with the dianions.
Ph
Ph
26
Figure
25Cp
2Zr[C(Ph)=C(Ph)OI
Figure 25 C*2Zr[C(Ph)=C(Ph)O]
62
EXPERIMENTAL SECTION
General Comments
All reactions were performed under an inert atmosphere using standard Schlenk
techniques. All solvents were distilled under nitrogen from the appropriate drying agents.
n-Butyllithium in hexane was purchased from Aldrich and titrated for RLi content by the
Gilman double-titrationmethod.27 1,1-Diphenylacetonewas purchased from Aldrich and
used without further purification. Acetone was dried over 3 A molecular sieves and
distilled prior to use. Tetramethylethylenediamine (TMEDA) was purchased from Aldrich
and distilled from calcium hydride before use. Potassium hydride was purified by washing
it with a THF solution of lithium aluminum hydride (approximately 4 mmol lithium
aluminum hydride in 10 mL of THF).28
1H NMR
spectra were obtained with a Varian XL-300 NMR spectrometer using
CDCl3 or C6 D6 as a reference at 7.24 ppm or 7.15 ppm downfield from tetramethylsilane,
respectively. Variable-temperature
1H
NMR spectra were obtained with a Varian XL-300
NMR spectrometer using toluene-d8 as a reference at 2.09 ppm downfield from
tetramethylsilane.
13 C NMR
spectra, both proton coupled and decoupled, were obtained
using a Varian XL-300 NMR spectrometer operating at 75.4 MHz in CDC13 or C6 D6 .
3 1p
NMR spectra were obtained using a Varian XL-300 NMR spectrometer operating at 121.4
MHz in CDC13 using 85% H3PO4 (0.00 ppm) as the external standard.
Electron impact mass spectra (MS) were obtained using a Finnigan-3200 mass
spectrometer operating at 70 eV. Infrared spectra (KBr) were obtained using a PerkinElmer 1600 Fourier Transform Infrared spectrophotometer. Melting points of analytically
pure crystalline and solid products were determined in air using a Biichi melting point
apparatus and are uncorrected. Elemental analyses were performed by the Scandinavian
Microanalytical Laboratory, Herlev, Denmark.
63
Vapor Pressure Osmometry
Molecular weight determinations were carried out using a Wescan Model 233
Molecular Weight Apparatus (vapor pressure osmometry). Vapor pressure osmometry
operates on the principle that the vapor pressure of a solution is lower than that of the pure
solvent at the same temperature, but by raising the temperature of the solution its vapor
pressure can be raised to match that of the solvent.
Equation 10 is derived from Raoult's
law and used for calculation of molecular weight.
AV=
KxC
(10)
m
where
A V = a voltage change
C = concentration
m = molecular weight
K = calibration factor
Sucrose octaacetate was used as a standard and all measurements were carried out
in chloroform. The calibration factor K was determined by measuring A V and C for the
known molecular weight of sucrose octaacetate (Mol. Wt. 678.6). By reversing the
procedure, unknown molecular weights are determined using that factor K.
Three different concentration of sucrose octaacetate solution were prepared. The
results for determination of calibration factor K are given in Table 9. The Wescan Model
233 Molecular Weight Apparatus were operated in the following condition:
Current: 50 microamperes.
Operating temperature: 400 C.
Average solvent reading: 2.0 microvolts.
64
Table 9. Determination of calibration factor K
Concentration
(mg/mL)
0.7
3.0
6.2
AV/C
Reading
AV
(microvolts)
(solution-solvent)
6.59
21.40
40.69
4.59
6.56
6.45
6.24
19.40
38.69
The determined values of AV/C are plotted versus concentration and a best fit
straight line is extrapolated to zero concentration. This extrapolated value of AV/C is used
to calculate the calibration factor K in equation 10 by multiplying it by the molecular weight
of the sucrose octaacetate. The extrapolates value is 6.62. The calibration factor K is
678.6 x 6.62 = 4492. The plot is show in Figure 26.
7.0
y a 6 .6 222 - 0.0592x R = 0.98
6.8
6.6Q 6.4
AV/C
< 6.2'
6.0
5.8
_
5.6I3
.I
1
2
3
4
5
6
C
Figure 26.
Calibration factor K for VPO
7
65
X-ray Crystallography
Structure of 7'
A X-ray diffraction study of 7' was performed by Dr. William M. Davis at the
Single Crystal X-ray Facility, department of Chemistry, MIT.
A yellow prismatic crystal of Zr2 C1202C 51 H46having approximate dimensions of
0.400 x 0.400 x 0.500 mm was mounted on a glass fiber. All measurements were made
on an Enraf-Nonius CAD-4 diffractometer with graphite monochromated Mo Ka radiation.
Cell constant and an orientation matrix for data collection, obtained from a least-
squires refinement using the setting angles of 25 carefully centered reflections in the range
12.00 < 20 < 24.00° , corresponded to a monoclinic cell with the dimensions given in
Table 10. For Z = 4 and F.W. = 944.27, the calculated density is 1.464g/cm3 . Based on
the systematic absences of h01: 1 2n and OkO:k * 2n and the successful solution and
refinement of the structure, the space group was determined to be P21/c ( #14).
The data were collected at a temperature of -80 ± 10 C using the c0-20 scan technique
to a maximum 20 valve of 55.60. Omega scans of several intense reflections, made prior to
data collection, had an average width at half-height of 0.270 with a take-off angle of 2.80.
Scans of (0.80 + 0.35 tan 0 ) were made at speeds ranging from 1.9 to 16.5° / min. (in
omega). Moving-crystal moving counter background measurements were made by
scanning an additional 25% above and below the scan range. The counter aperture
consisted of a variable horizontal slit with a width ranging from 2.0 to 2.5 mm and a
vertical slit set to 2.0 mm. The diameter of the incident beam collimator was 0.7 mm and
the crystal to detector distance was 21 cm. For intense reflections an attenuator was
automatically inserted in front of the detector.
Of the 10668 reflections which were collected, 10293 were unique (Rint = .080);
equivalent reflections were merged. The intensities of three representative reflections
66
which were measured after every 60 minutes of X-ray exposure time declined by -5.50%.
A linear correction factor was applied to the data to account for this phenomenon.
The linear absorption coefficient for Mo Ka is 6.4 cm-1 . An empirical absorption
correction, using the program DIFABS 2 9 , was applied which resulted in transmission
factors ranging from 0.90 to 1.07. The data were corrected for Lorentz and polarization
effects. A correction fro secondary extinction was applied (coefficient = 0.17909E-06).
The structure was solved by directed methods30 . The non-hydrogen atoms were
refined anisotropically. The final cycle of full-matrix least-squares refinement 3 1 was based
on 6171 observed reflections (I > 3.00a(I)) and 524 variable parameters and converged
(largest parameter shift was 0.22 times its esd) with unweighted and weighted agreement
factors of R = 0.051 and R w = 0.042.
The standard deviation of an observation of unit weight 32 was 1.45. The
weighting scheme was based on counting statistics and included a factor (p = 0.02) to
downweight the intense reflections. Plots of Iw(IFol - IFc1)2 versus IFol,reflection order in
data collection, sin 0/k, and various classes of indices showed no unusual trends. The
maximum and minimum peaks on the final difference Fourier map corresponded to 0.65
and -0.66 e-/A3 , respectively.
Neutral atom scattering factors were taken from Cromer and Waber 3 3 . Anomalous
dispersion effects were included in Fcalc34 ; the values for Af' and Af" were those of
Cromer3 5 . All calculations were performed using the TEXSAN3 6 crystallographic
software package of Molecular Structure Corporation.
During the solution of the structure a solvent molecule was located on a difference
Fourier map. The solvent molecule was identified as methylene chloride moiety based
upon chemical information. As refinement proceeded the moiety was noticeably disordered
in one chlorine atom. The top two peaks (C12and C13)in the region were assigned onehalf occupancy chlorine and eventually refined anisotropically to their current values.
67
Average distances and angles within the solvent molecule are consistent with methylene
chloride and no other chemically significant peaks were found near the moiety.
68
Table 10. Crystal data for 7'
Empirical formula
Zr2C1202C 5 1H46
Formula Weight
944.27
Crystal Color; Habit
yellow, prismatic
Crystal Dimensions (mm)
0.400 x 0.400 xO.500
Crystal System
No. Reflections Used for Unit
monoclinic
Cell Determination (20 range)
25 (12.0- 24.0° )
Omega Scan Peak Width at Hal-height
0.27
Lattice Parameters:
a= 15.318 (2)
A
b= 18.155(2) A
= 16.384(2) A
[ = 109.89(3) °
V = 4285(2) A 3
Space group
P21/c (#14)
Z value
4
Dcalc
1.464 g/cm 3
F000
1928
(MoKa)
6.42 cm 1
69
Table 11. Intensity Measurements for 7'.
Radiation
Enraf-Nonius CAD-4
MoKa ( = 0.71069 A)
Temperature
-80 °
Attenuator
Zr foil, (factor = 17.9)
Take-off Angle
2.8°
Detector Aperture
2.0-2.5 mm horizontal
Crystal to detector Distance
2.0 mm vertical
21 cm
Diffractometer
Scan Type
- 20
Scan Rate
1.9 - 16.5 0 /min (in omega)
Scan Width
(0.80 + 0.35 tanO)°
20
55.6°
max
No. of Reflections Measured
Total: 10688
Unique: 10293 (Rint = 0.080)
Corrections
Lorentz-polarization
70
Table 12 Structure solution and refinement for 7'
Structure Solution
Direct Methods
Refinement
Function Minimized
;w(IFo
Least-squares Weights
4Fo 2 /a2 (Fo 2 )
p-factor
Anomalous Dispersion
0.02
No. Observations (I > 3.00a(I)
6171
No. Variables
524
Reflection/Parameter Ratio
Residuals: R; R w
11.78
0.051; 0.042
Goodness of Fit Indicator
1.45
Max Shift/Error in Final Cycle
0.22
Maximum Peak in Final Diff. Map
0.65 e-/A 3
Minimum Peak in Final Diff. Map
-0.66 e-/A 3
Full-Matrix Least-Squares
- IFcI)2
All non-hydrogen atoms
71
Table 13. Final position parameters for 7'.
Atom
x
y
z
Zr(l)
0.37828(3)
0.09072(3)
0.6816(1)
0.6037(4)
0.6286(5)
0.3181(2)
0.1632(2)
0.2455(3)
0.1859(3)
0.1571(3)
0.1787(3)
0.2761(3)
0.3247(3)
0.1658(3)
0.1970(4)
0.2020(4)
0.1727(5)
0.1412(4)
0.1368(4)
0.1080(3)
0.1551(3)
0.1076(5)
0.24059(2)
0.30486(2)
0.1628(2)
0.0248(4)
0.0121(4)
0.3246(2)
0.2156(1)
0.1747(2)
0.1563(2)
0.0892(2)
0.3834(2)
0.3909(2)
0.4520(2)
0.0214(3)
-0.0433(3)
-0.1077(3)
-0.1097(3)
-0.0472(4)
0.0180(3)
0.0801(2)
0.0797(3)
0.0714(3)
0.0642(3)
0.0628(3)
0.0709(3)
0.5278(2)
0.5826(3)
0.6536(3)
0.6710(3)
0.6184(3)
0.5478(3)
0.4475(2)
0.4216(3)
0.4166(4)
0.4368(4)
0.4640(3)
0.4681(3)
0.2357(3)
0.2970(4)
0.3565(3)
0.3318(5)
0.2560(5)
0.2808(3)
0.3311(3)
0.3976(3)
0.3867(3)
0.3145(3)
0.2205(4)
0.2295(4)
0.21745(3)
0.23184(3)
0.5677(1)
0.5773(4)
0.5194(5)
0.2508(2)
0.2356(2)
0.1455(3)
0.1974(3)
0.2127(3)
0.1777(3)
0.2294(3)
0.2607(3)
0.1658(3)
0.2101(3)
0.1685(4)
0.0794(5)
0.0343(4)
0.0763(3)
0.2763(3)
0.3652(3)
0.4236(3)
0.3947(4)
0.3089(4)
0.2506(3)
0.2327(3)
0.2930(3)
0.2670(5)
0.1831(6)
0.1223(4)
0.1469(4)
0.3231(3)
0.4044(3)
0.4625(4)
0.4401(4)
0.3598(4)
0.3020(3)
0.1091(4)
0.0729(3)
0.1038(4)
0.1596(5)
0.1628(4)
0.3904(3)
0.3816(3)
0.3520(3)
0.3430(3)
0.3649(3)
0.0728(4)
0.1314(5)
Zr(2)
Cl(1)
C1(2)
C1(3)
0(1)
0(2)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(20)
C(21)
C(22)
C(23)
C(24)
C(25)
C(30)
C(31)
C(32)
C(33)
C(34)
C(35)
C(40)
C(41)
C(42)
C(43)
C(44)
C(45)
C(50)
C(51)
C(52)
C(53)
C(54)
C(55)
C(56)
C(57)
C(58)
C(59)
C(60)
C(61)
0.0151(5)
-0.0331(4)
0.0139(3)
0.2909(3)
0.2974(3)
0.2684(4)
0.2325(5)
0.2275(4)
0.2566(4)
0.4200(3)
0.4376(4)
0.5258(5)
0.5998(4)
0.5849(4)
0.4959(4)
-0.0220(4)
-0.0015(4)
-0.0343(4)
-0.0776(4)
-0.0678(4)
0.1317(4)
0.1948(3)
0.1480(4)
0.0555(4)
0.0453(4)
0.3976(5)
0.4854(5)
72
C(62)
C(63)
C(64)
C(65)
C(66)
C(77)
C(68)
C(69)
C(70)
0.4922(5)
0.4112(6)
0.3525(4)
0.4917(4)
0.5174(4)
0.4500(4)
0.3815(4)
0.4077(4)
0.5952(5)
0.3015(5)
0.3358(3)
0.2869(4)
0.1441(4)
0.2090(4)
0.2271(3)
0.1752(3)
0.1228(3)
0.1025(5)
0.1613(4)
0.1202(5)
0.0669(4)
0.2968(4)
0.3436(4)
0.3784(3)
0.3531(3)
0.3035(4)
0.5248(5)
73
Table 14
Intramolecular bond distances (A) for 7' , involving the non-hydrogen
atoms.
Atom
Atom
Distance
Atom
Atom
Distance
Zr(l)
0(1)
C(1)
C(60)
C(61)
C(62)
C(63)
C(64)
C(65)
C(66)
C(67)
C(68)
C(69)
1.954(3)
2.307(4)
2.513(5)
2.508(5)
2.491(6)
2.516(6)
2.507(5)
2.498(5)
2.479(5)
2.500(5)
2.505(5)
2.516(5)
C1(2)
C1(3)
C(70)
C(70)
C(5)
C(2)
C(2)
C(3)
C(10)
C(20)
C(5)
C(6)
C(30)
C(40)
1.634(9)
Zr(l)
Zr(l)
Zr(l)
Zr(l)
Zr(l)
Zr(l)
Zr(l)
Zr(l)
Zr(l)
Zr(l)
Zr(l)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr((2)
Zr(2)
Zr(2)
Cl(1)
0(2)
1.953(3)
C(4)
2.335(4)
2.498(5)
2.508(5)
2.493(5)
2.492(5)
2.468(6)
2.495(5)
2.476(5)
2.511(5)
2.547(5)
2.511(5)
C(50)
C(51)
C(52)
C(53)
C(54)
C(55)
C(56)
C(57)
C(58)
C(59)
C(70)
C1(2)
C(31)
C(33)
C(40)
C(41)
C(43)
C(3)
C(50)
C(51)
C(53)
C(51)
C(52)
C(55)
C(57)
C(60)
C(61)
C(63)
C(65)
C(67)
C(32)
C(34)
C(41)
C(42)
C(44)
C(54)
C(59)
C(58)
C(61)
C(62)
C(64)
C(69)
C(68)
1.677(8)
1.160(7)
1.383(8)
1.362(9)
1.351(6)
1.365(7)
1.350(7)
1.347(8)
1.359(8)
1.383(9)
1.388(7)
1.389(7)
1.370(8)
1.386(9)
1.353(8)
1.383(7)
1.365(7)
0(1)
0(2)
C(1)
C(2)
C(3)
C(3)
C(4)
C(5)
C(6)
C(6)
C(10)
C(10)
C(11)
C(12)
C(13)
C(14)
C(20)
C(20)
C(11)
C(15)
C(12)
C(13)
C(14)
C(15)
C(21)
C(21)
C(25)
C(22)
C(22)
C(23)
C(23)
C(24)
C(25)
C(24)
C(30)
C(30)
C(32)
C(34)
C(40)
C(42)
C(44)
C(50)
C(52)
C(55)
C(56)
C(58)
C(60)
C(62)
C(65)
C(66)
C(68)
C(31)
C(35)
C(33)
C(35)
C(45)
C(43)
C(45)
C(54)
C(53)
C(56)
C(57)
1.73(1)
1.354(5)
1.350(5)
1.483(6)
1.349(5)
1.481(6)
1.488(6)
1.450(6)
1.337(6)
1.487(6)
1.472(6)
1.379(6)
1.381(6)
1.368(7)
1.375(8)
1.349(8)
1.383(7)
1.388(6)
1.367(6)
1.393(7)
1.340(7)
1.348(7)
1.385(6)
1.381(6)
1.372(6)
1.333(9)
1.372(7)
1.374(6)
1.356(8)
1.372(7)
1.383(9)
C(59)
C(64)
1.374(9)
1.374(7)
1.404(7)
1.383(7)
1.377(8)
C(63)
1.347(9)
C(66)
C(67)
C(69)
1.387(8)
1.379(7)
1.396(7)
74
Table 15 Intramolecular bond angles () for 7', involving the non-hydrogen atoms.
Atom
0(1)
0(1)
0(1)
0(1)
0(1)
0(1)
0(1)
0(1)
Atom
Atom
Zr(1)
C(1)
C(60)
Zr(l)
Zr(l)
Zr(l)
Zr(1)
Zr(l)
Zr(l)
Zr(l)
0(1)
0(1)
0(1)
Zr(1)
C(1)
C(1)
C(1)
C(1)
C(1)
C(1)
C(1)
C(1)
Zr(l)
Zr(l)
C(1)
Zr(1)
C(1)
C(60)
C(60)
C(60)
C(60)
C(60)
C(64)
C(64)
C(64)
C(64)
C(65)
C(65)
C(65)
C(65)
C(66)
C(66)
C(66)
C(67)
C(67)
C(68)
Zr(l)
Zr(l)
0(2)
0(2)
0(2)
0(2)
0(2)
0(2)
0(2)
0(2)
0(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(l)
Zr(1)
Zr(1)
Zr(l)
Zr(l)
Zr(l)
Zr(1)
Zr(l)
C(61)
C(62)
C(63)
C(64)
C(65)
C(66)
C(67)
C(68)
C(69)
C(60)
C(61)
C(62)
C(63)
C(64)
C(65)
C(66)
C(67)
C(68)
C(69)
C(61)
Zr(1)
C(62)
Zr(l)
Zr(l)
Zr(l)
Zr(l)
Zr(l)
C(63)
Zr(1)
Zr(l)
Zr(l)
Zr(l)
Zr(l)
Zr(l)
Zr(1)
Zr(1)
Zr(l)
Zr(l)
Zr(l)
Zr(l)
C(64)
C(65)
C(66)
C(67)
C(68)
C(69)
C(66)
C(67)
C(68)
C(69)
C(67)
C(68)
C(69)
C(68)
C(69)
C(69)
C(4)
C(50)
C(51)
C(52)
C(53)
C(54)
C(55)
C(56)
C(57)
Angle
97.5(1)
126.5(2)
132.9(2)
102.3(2)
81.7(2)
94.7(2)
135.4(2)
107.5(2)
82.0(2)
89.5(2)
121.2(2)
79.0(2)
107.6(2)
130.4(2)
111.4(2)
81.6(2)
103.8(2)
131.6(2)
118.9(2)
87.5(2)
78.7(2)
31.7(2)
52.7(2)
52.4(2)
31.8(2)
96.0(2)
134.5(2)
159.5(2)
168.7(2)
140.8(2)
32.4(2)
53.4(2)
53.5(2)
32.0(2)
32.1(2)
53.0(2)
52.9(2)
31.7(2)
52.8(2)
32.3(2)
97.1(1)
80.7(2)
95.7(2)
127.2(2)
131.5(2)
100.2(2)
83.3(1)
87.7(2)
119.2(2)
Atom
Atom
C(60)
C(60)
C(60)
C(60)
C(61)
C(61)
C(61)
C(61)
C(61)
C(61)
C(61)
C(61)
C(62)
C(62)
C(62)
C(62)
C(62)
C(62)
C(62)
C(63)
C(63)
C(63)
C(63)
C(63)
C(63)
C(64)
C(4)
C(4)
C(4)
C(4)
C(4)
C(4)
C(4)
C(4)
C(4)
Zr(l)
Atom
C(66)
Zr(l)
C(67)
Zr(1)
C(68)
C(69)
C(50)
C(50)
C(50)
C(50)
C(50)
C(50)
C(50)
C(50)
C(50)
C(51)
C(51)
C(51)
C(51)
C(51)
Zr(l)
Zr(l)
Zr(l)
Zr(l)
Zr(l)
Zr(l)
Zr(l)
Zr(l)
Zr(1)
Zr(l)
Zr(1)
Zr(l)
Zr(l)
Zr(l)
Zr(l)
Zr(1)
Zr(l)
Zr(l)
Zr(l)
Zr(l)
Zr(l)
Zr(l)
Zr(l)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
C(62)
C(63)
C(64)
C(65)
C(66)
C(67)
C(68)
C(69)
C(63)
C(64)
C(65)
C(66)
C(67)
C(68)
C(69)
C(64)
C(65)
C(66)
C(67)
C(68)
C(69)
C(65)
C(51)
C(52)
C(53)
C(54)
C(55)
C(56)
C(57)
C(58)
C(59)
C(51)
C(52)
C(53)
C(54)
C(55)
C(56)
C(57)
C(58)
C(59)
C(52)
C(53)
C(54)
C(55)
C(56)
Angle
114.1(2)
146.1(2)
142.6(2)
110.4(2)
32.2(2)
52.3(2)
52.3(2)
76.4(2)
84.8(2)
116.6(2)
129.9(2)
102.7(2)
31.2(2)
52.0(2)
93.0(3)
84.2(2)
108.7(2)
137.1(2)
124.7(3)
31.2(2)
123.9(2)
112.7(2)
128.6(2)
160.0(2)
154.5(2)
126.6(2)
80.5(2)
80.1(2)
109.7(3)
130.6(2)
122.0(2)
89.9(2)
78.2(2)
101.9(2)
130.9(2)
31.2(2)
52.3(2)
52.9(2)
31.6(2)
127.6(2)
158.5(2)
158.4(2)
127.8(2)
114.5(2)
31.5(2)
52.5(2)
52.1(2)
157.6(2)
170.1(2)
75
0(2)
0(2)
C(4)
C(52)
C(52)
C(52)
C(52)
C(52)
C(52)
C(52)
C(53)
C(53)
C(53)
C(53)
C(53)
C(53)
C(54)
C(54)
C(54)
C(54)
C(54)
C(55)
C(SS)
C(SS)
C(55)
C(56)
C(56)
C(56)
C(57)
C(13)
C(10)
C(3)
C(3)
C(21)
C(20)
C(21)
C(22)
C(23)
C(20)
C(6)
C(6)
C(31)
C(30)
C(31)
C(32)
C(33)
C(30)
C(6)
C(6)
C(41)
C(40)
C(41)
C(42)
C(43)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
C(14)
C(15)
C(29)
C(20)
C(20)
C(21)
C(22)
C(23)
C(24)
C(25)
C(30)
C(30)
C(30)
C(31)
C(32)
C(33)
C(34)
C(35)
C(40)
C(40)
C(40)
C(41)
C(42)
C(43)
C(44)
C(58)
C(59)
C(50)
C(53)
C(54)
C(55)
C(56)
C(57)
C(58)
135.9(2)
109.3(2)
109.3(2)
32.0(2)
52.8(2)
142.3(2)
144.4(2)
111.8(2)
95.3(2)
C(59)
110.1(2)
C(54)
32.4(2)
C(55)
C(56)
112.5(2)
130.3(2)
105.6(2)
C(57)
C(58)
C(59)
C(55)
C(56)
C(57)
C(58)
C(59)
C(56)
C(57)
C(58)
C(59)
C(57)
C(58)
C(59)
C(58)
C(15)
C(14)
C(21)
C(25)
C(25)
C(22)
C(23)
C(24)
C(25)
C(24)
C(31)
C(35)
C(35)
C(32)
C(33)
C(34)
C(35)
C(34)
C(41)
C(45)
C(45)
C(42)
C(43)
C(44)
C(45)
77.8(2)
81.4(2)
105.9(2)
136.5(2)
128.8(3)
97.0(3)
84.4(2)
32.1(2)
53.4(2)
52.9(2)
32.2(2)
32.7(2)
53.2(2)
53.2(2)
31.9(2)
121.1(6)
120.9(5)
121.9(4)
122.0(4)
116.2(4)
120.9(5)
120.4(5)
120.5(5)
119.3(5)
122.7(5)
120.8(5)
122.2(4)
116.9(5)
120.9(6)
121.0(6)
119.3(6)
120.5(6)
121.4(5)
121.5(4)
122.3(4)
116.2(5)
122.0(5)
120.8(6)
118.9(5)
119.4(5)
C(51)
C(51)
C(51)
C(57)
C(58)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
Zr(2)
C1(3)
C1(2)
C1(2)
C1(3)
Zr(1)
Zr(2)
Zr(1)
0(1)
0(2)
0(2)
C(1)
C(2)
C(2)
C(10)
Zr(2)
0(1)
0(1)
C(4)
C(S)
C(S)
C(30)
C(3)
C(3)
C(11)
C(10)
C(11)
C(12)
Zr(2)
Zr(2)
C(51)
Zr(2)
Zr(2)
C(50)
Zr(2)
Zr(2)
C(51)
Zr(2)
Zr(2)
C(52)
Zr(2)
Zr(2)
C(50)
Zr(2)
Zr(2)
C(56)
Zr(2)
Zr(2)
C(55)
Zr(2)
Zr(2)
C(56)
Zr(2)
0(2)
C(1)
C(2)
C(2)
C(2)
C(3)
C(3)
C(3)
C(4)
C(S)
C(S)
C(S)
C(6)
C(6)
C(6)
C(10)
C(10)
C(10)
C(11)
C(12)
C(13)
C(SO)
C(SO)
C(50)
C(51)
C(51)
C(51)
C(52)
C(52)
C(52)
C(53)
C(53)
C(53)
C(54)
C(54)
C(54)
C(55)
C(55)
C(55)
C(56)
C(56)
C(56)
C(57)
C(57)
C(57)
C(58)
C(57)
C(58)
C(59)
C(59)
C(59)
C(70)
C(70)
C(S)
C(2)
C(2)
C(1)
C(3)
C(3)
C(10)
C(20)
C(20)
C(S)
C(4)
C(6)
C(6)
C(30)
C(40)
C(40)
C(11)
C(15)
C(15)
C(12)
C(13)
C(14)
C(51)
C(54)
C(54)
C(50)
C(52)
C(52)
C(51)
C(53)
C(53)
C(52)
C(54)
C(54)
C(50)
C(53)
C(53)
C(56)
C(59)
C(59)
C(55)
C(57)
C(%7)
C(56)
C(58)
C(58)
C(57)
140.8(2)
126.4(2)
132.9(2)
53.0(2)
31.7(2)
74.4(6)
65.4(5)
148.2(3)
151.7(3)
115.6(3)
113.1(4)
118.9(4)
127.9(4)
124.2(4)
120.4(4)
115.3(4)
116.6(3)
111.8(4)
119.0(4)
129.1(4)
124.0(4)
120.7(4)
115.2(4)
120.7(4)
122.4(4)
116.7(5)
122.2(5)
119.9(6)
119.0(5)
74.8(2)
73.0(3)
108.1(6)
74.0(3)
73.6(3)
108.8(6)
74.9(3)
74.0(3)
108.2(6)
74.0(3)
72.9(3)
106.2(6)
75.4(3)
74.7(4)
108.7(6)
73.2(3)
74.5(3)
108.0(5)
74.7(3)
75.0(3)
108.2(5)
72.3(3)
75.5(3)
107.3(5)
72.7(3)
76
C(40)
C(57)
Zr(2)
Zr(2)
C(55)
Zr(1)
Zr(1)
C(61)
Zr(1)
Zr(1)
C(60)
Zr(1)
Zr(1)
Zr(1)
C(62)
Zr(1)
Zr(1)
C(66)
Zr(1)
Zr(1)
C(45)
C(58)
C(59)
C(59)
C(59)
C(60)
C(60)
C(60)
C(61)
C(61)
C(61)
C(62)
C(62)
C(63)
C(63)
C(64)
C(65)
C(65)
C(66)
C(67)
C944)
122.6(5)
C(59)
108.0(5)
C(55)
C(58)
C(58)
C(61)
C(64)
C(64)
C(60)
C(62)
C(62)
C(61)
C(63)
C(62)
73.3(3)
75.6(3)
108.4(5)
74.0(3)
73.9(3)
107.1(6)
74.4(3)
73.2(3)
Zr(2)
Zr(1)
C(66)
Zr(1)
Zr(1)
C(67)
Zr(1)
Zr(1)
C(65)
C1(1)
107.4(6)
Cl(1)
74.6(4)
75.4(4)
73.4(4)
C1(2)
C(64)
108.4(6)
C(63)
C(66)
C(69)
C(67)
C(66)
74.7(4)
73.1(3)
106.9(5)
74.8(3)
73.1(3)
C(61)
Zr(1)
Zr(1)
C(60)
Zr(1)
Zr(1)
C(65)
C(58)
C(67)
C(67)
C(68)
C(68)
C(68)
C(69)
C(69)
C(69)
C(70)
C(70)
C(70)
C(62)
C(63)
C(64)
C(64)
C(65)
C(66)
C(66)
C(59)
C(68)
C(68)
C(67)
C(69)
C(69)
C(65)
C(68)
C(68)
C1(2)
C1(3)
C1(3)
C(63)
C(64)
C(60)
C(63)
C(69)
C(65)
C(67)
72.7(3)
74.4(3)
108.4(5)
74.0(3)
74.3(3)
107.7(5)
73.3(3)
73.5(3)
108.3(5)
115.6(5)
115.8(5)
40.2(3)
108.3(6)
74.0(3)
74.3(3)
108.8(6)
74.7(3)
74.6(3)
108.6(5)
77
2
Preparation of 1,1-Diphenylacetone Dianion [Ph 2 CC(O)CH 2 ] - (6a) (TW-I-
72, II-6)
2
1,-Diphenylacetone dianion, [Ph2 CC(O)CH2 ] - (6a), was prepared according to a
literature procedure. 5C A 100 mL round-bottomed Schlenk flask equipped with a magnetic
stir bar and a rubber septum was charged with 0.5 g (12.5 mmol) of potassium hydride
of
and 50 mL of THF. A solution of 1,1-diphenylacetone (2.62 g, 12.5 mmol) in 10 mL
THF was added slowly to the flask by cannula. Hydrogen gas evolution was observed.
To
After stirring at room temperature for 15-20 min, a clear orange solution was obtained.
this orange solution at 0°C, one molar equivalent of n-butyllithium was added (7.8 mL of a
at
1.6 M solution). The resulting red mixture was stirred at 0°C under argon for 5-7 min.,
which point it was ready for further reaction.
Preparation of Acetone Dianion [CH 2 C(O)CH 2 ]2- (6b) (TW-11-28)
2
Acetone dianion, [CH2 C(O)CH2] - (6b), was prepared according to a literature
procedure.5 e A 100 mL round-bottomed Schlenk flask equipped with a magnetic stir bar
and a rubber septum was charged with 0.5 g (12.5 mmol) of potassium hydride and 50 mL
of Et O. Acetone (0.91 mL, 12.5 mmol) was added slowly to the flask by syringe.
2
Hydrogen gas evolution was observed. After stirring at room temperature for 20 min,
°
potassioacetone was obtained. To this white suspension at 0 C, one molar equivalent of n-
butyllithium (7.8 mL of a 1.6 M solution) and one molar equivalent of
tetramethylethylenediamine were added. The resulting yellow mixture was stirred at 0°C
under argon for 5-7 min, at which point it was ready for further reaction.
Preparation of CpzZrCHC(=CPh2)O, 7 (TW-II-16, 20, 30, III-49)
A 250 mL round-bottomed Schlenk flask equipped with a magnetic stir bar
and a rubber septum was charged with 3.64 g (12.5 mmol) of Cp2 ZrCI2 and 100 mL of
78
THF. To this solution at - 78C was added slowly by cannula 12.5 mmol of 1,1diphenylacetone dianion 1 in 50 mL of THF. The resulting mixture was allowed to warm
slowly to room temperature and was stirred overnight. The resulting orange suspension
was evaporated at reduced pressure. The residue was extracted with 3x 100 mL of toluene.
Filtration through Celite was followed by concentration of the orange filtrate to about 30
mL and addition of 150 mL of hexane. The resulting yellow precipitate was washed twice
with hexane and dried in vacuo. Compound 7 was obtained as a yellow crystalline solid,
3.2 g (58%), after recrystallization from toluene. The analytical and crystallographic
samples were obtained by slow diffusion of hexane into a concentrated solution of the
yellow solid in CH 2C12 . A CH 2C12 solvate was obtained (CH2 C12 can be removed by
drying in vacuo overnight at 50C), mp 185-187C dec.
1H
NMR (300 MHz, C 6 D 6 , containing CH 2 C12 ): 8 1.81 (br s, 2 H), 4.25 (s, CH 2 C12 ),
5.51 (br s, 5 H), 6.00 (br s, 5 H), 7.10-7.70 (m, 10).
13 C
NMR (75.4 MHz, CDC13 ):
46.9 (t, J = 121 Hz, CH2 ), 108.2 (s, C =CPh 2 ),
111.1 (d, J = 175 Hz, C 5 H 5 ), 124.0-145.1(m, Ph),170.1 (t, 2J = 5 Hz,
CH 2 C---CPh2 ).
MS (EI, 90Zr) Calcd. for C5 0H44Zr2 0 2 : 856; Found: m/z (relative intensity): 856 ( 2M+ ,
12), 664 (2M + - CH 2 C=CPh 2 , 29), 428 (M + , 100), 363 (M + - Cp, 9), 236
(Cp2Zr=O, 24), 220 (Cp2Zr, 81), 192 (Ph2CCCH2, 50), 166 (CPh2), 77 (Ph,
4), 69 (15)
IR ( KBr, cm-l): 3049(w), 2951(w), 2853(w), 1574(s), 1561(s), 1491(w), 1438(w),
1238(s), 1192(m), 1018(m), 1001(m), 983(m), 808(s), 699(m).
79
Anal. Calcd. for C50 H44Zr02CH
2
2 C12 :
C, 64.85; H, 4.92. Cl, 7.51. Found: C, 64.56;
H, 4.91; Cl, 7.60.
Mol wt. (VPO, CHCl 3, CH2 C12 -free sample): Calcd. for C2 5 H22 ZrO: 429; Found:
410
Three different concentrations of 7 were prepared and A V values were
determined. The data was given in Table 16. A plot of A V/C versus C (Figure 27)
was prepared and the zero concentration intercept was used to calculate the molecular
weight. The extrapolated value is 10.95. The molecular weight is then calculated to be
4492/10.95 = 410 g/mol.
Table 16. Determination of molecular weight of 7
Concentration
Reading
AV
(mg/mL)
(microvolts)
(solution-solvent)
1.1
13.99
11.99
10.90
3.2
36.72
34.72
10.85
6.3
69.41
67.41
10.70
AV/C
80
11.3
y - 10.9552- 0.0392x R - 0.99
11.1 -
.0.9-
A V/C
10.7 IAc,
LU.3
.I
0
1
I
-
2
3
w
.w
4
5
.!~~~~~~~~~
6
7
C
I
-
Figure 26.
Variable-temperature
1H
I
VPO data for Cp2 ZrCH 2 C(=CPh 2)O, 7
NMR (toluene - d8 , 300 MHz,):
slow exchange limit, -17C:
6 1.86 (d, J = 11 Hz, 1 H), 2.00 (d, J = 11 Hz, 1 H), 5.56 (s, 5 H), 6.07 (s, 5
H), 7.10-.67 (m, 10 H).
coalescence temperature, 500 C:
6 1.80 (s, 2 H), 5.73 (bs, 10 H), 6.95-7.55 (m, 10 H)
fast exchange limit, 90C:
6 1.91 (s, 2 H), 5.88 (s, 10 H) 7.10-7.70 (m, 10 H).
I
Preparation of CHfCH2C(=CPh
--
I
2)0, 8 (TW-IV-5, 38, 42)
A red THF solution of the dianion 6a derived from 2.62 g (12.5 mmol) of 1,1diphenyl-2-propanone
was added dropwise to a solution of 4.72 g (12.5 mmol) of
81
Cp2 HfC12in 100 mL of THF solution under N2 at -780 C (eq. 3). The resulting mixture
was allowed to warm slowly to room temperature and was stirred overnight. The orange
suspension was evaporated at reduced pressure. The residue was extracted with 3x100 mL
of toluene. Filtration through Celite was followed by concentration of the orange filtrate to
-30 mL and addition of 150 mL of hexane. The resulting yellow precipitate was washed
twice with hexane and dried in vacua. Compound, 8, was obtained as a yellow crystalline
solid, 3.3 g (50%), after recrystallization from toluene, mp 215-218 0 C dec.
1H
NMR (300 MHz, C6 D6 ): 8 1.54 (br s, 1 H), 1.70 (br s, 1H). 5.50 (br s, 5 H), 5.95
(br s, 5 H), 7.05-7.58 (m, 10).
13 C
NMR (75.4 MHz, CDC13): 48.3 (t, J = 120 Hz, CH2 ), 110.1 (s, C=CPh 2), 110.5
(d, J = 171 Hz, C 5 H 5 ), 124.6-145.6 (m, Ph), 170.1 (t, 2J = 5 Hz,
CH2 C=CPh2).
MS (El,
180 Hf)
Calcd. for C50 H44Hf2 02 : 1036; Found: m/z (relative intensity): 1036 (
2M + , 27), 844 (2M + - CH 2 C=CPh 2, 87), 585 (97), 567 (15), 518 (M+,
70), 453(M + - Cp, 30), 326 (Cp2Hf=O, 19), 220(10), 192 (Ph2CCCH2 , 35),
166 (CPh2, 62), 69(23)
IR (KBr, cm-l): 3050(w), 2941(w), 2868(w), 1578(s), 1563(s), 1490(m), 1440(m),
1252(s), 1193(w), 1154(w), 1033(m), 1018(m), 1002(m), 985(m), 810(s),
772(m), 754(w), 700(s).
Anal. Calcd. for C5 0 H44Hf20 2 : C, 58.08; H, 4.30. Found: C, 58.19; H, 4.35.
Mol wt. (VPO, CHC13 ) Calcd. for C25 H22 HfO: 517; Found: 499.
82
Variable-temperature
1H
NMR (toluene - d8 , 300 MHz,):
slow exchange limit, 130 C:
6 1.61 (d, J = 12 Hz, 1 H), 1.82 (d, J = 12 Hz, 1 H), 5.57 (s, 5 H), 6.04 (s, 5
H), 7.11-7.66 (m, 10 H).
coalescence temperature, 450 C:
6 1.60 (br s, 2 H), 5.69 (br, s, 10 H), 6.99-7.53 (m, 10 H)
fast exchange limit, 90C:
8 1.60 (s, 2 H), 5.75 (s, 10 H), 7.01-7.52 (m, 10 H).
Calculation of free activation energy, AG:
two Cp resonances are separated by 0.47 ppm at slow exchange limit and at 300 MHz
AS = 6.04-5.57 = 0.47 ppm (300 MHz) = 141 Hz
and thus, at the coalescence temperature (45°C)
k=,,
R (As)
2
r (141 s l)
= 31381
42
The Eyring equation gives the relationship of the rate constant to AG
k = (cT/h) e -AG RT
thus,
AG= -RT[ln (kT) + ln (h/)]
where
R = 1.987 x 10-3kcal/mol.K
K = Boltzmnann'sconstant
= 1.38054 x 10-16erg/k
83
h = Planck's constant = 6.6256 x 10-27 erg-sec
T = temperature in K
thus, for complex 8
AG = 15.0 kcal/mol
Preparation of( 15-CSH4C 3) 2 ZrCH 2C(=CPh2 )O, 9(TW-IV-27, 29, 34, 43)
A red THF solution of the dianion 6a derived from 1.31 g (6.3 mmol) of 1,1diphenyl-2-propanone was added dropwise to a solution of 2 g (6.3 mmol) of
(r15 -C5 H4 CH3)2 ZrCI2 in 100 mL of THF solution under N2 at -780 C (eq. 3). The resulting
mixture was allowed to warm slowly to room temperature and was stirred overnight. The
orange suspension was evaporated at reduced pressure. The residue was extracted with
3x100 mL of toluene. Filtration through Celite was followed by concentration of the
orange filtrate to about 15 mL. About 100 mL of hexane was layered on the top of the
toluene solution. An orange crystalline product and a yellow solid were obtained on
storing the toluene and hexane solution at -23°C for one week. The yellow solid (about 1.5
g), which could not be identified, was carefully removed by spatula in the dry box. The
orange crystalline product was washed with cold hexane and redissolved in toluene.
Filtration of toluene solution gave an clear orange solution. A fine yellow solid 9, 0.86 g
(30%), was obtained after recrystallization from toluene and dried in vacuo, mp 161-164°C
dec. However, there is approximately 5-10% impurity, which could not be removed by
repeated recrystallization from toluene and methylene chloride solution.
1H
NMR (300 MHz, C6 D6 ): 8 1.70 (br d, 6 H), 1.84 (br, s, 2 H), 5.49 (br d, 4 H),
6.10 (br d, 4 H), 7.10-7.60 (m, 10).
6.05 (br, impurity)
84
13 C
NMR (75.4 MHz, C6D6):
14.7 (q, J = 125, CH 3 ), 48.9 (t, J = 122, CH 2 ),
108.2 (s, C=CPh 2), 111.6-115.6 (m, C5 H4 Me), 124.2-146.1 (m, Ph), 171.6
(s, CH2 C=CPh 2).
MS (EI, 90Zr) Calcd. for C54 H52 Zr
02
2:
912; Found: m/z (relative intensity): 912 ( 2M+ ,
15), 720 (2M+ - CH 2 C=CPh 2 , 5), 456 (M+ , 100), 377 (M+ - Cp, 41), 248
((CpMe)2Zr, 36), 192 (Ph2CCH2, 30), 79 (CpMe, 5).
IR ( KBr, cm-1): 3048(w), 2926(w), 2864(w), 1596(m), 1576(s), 1550(s), 1484(s),
1438(m), 1381(w), 1314(m), 1233(s), 1187(m), 1099(w), 1028(w), 1003(s),
977(s), 798(s), 767(s).
Anal. Calcd. for C54 H 52 Zr02
Variable-temperature
1H
2:
C, 70.84; H, 5.74. Found: C, 69.25; H, 5.75.
NMR (toluene - d8 , 300 MHz,):
slow exchange limit, -17C:
5 1.53 (s, 3 H), 1.70 (s, 3 H), 1.73 (d, J = 11 Hz, 1 H), 1.87 (d, J = 11 Hz, 1
H), 5.50 (m, 4 H), 6.10 (m, 4 H), 7.10-7.55 (m, 10 H).
coalescence temperature, 600 C:
8 1.68 (br s, 6 H), 1.80 (br s, 2 H), 5.69 (br s, 8 H), 6.98-7.50 (m, 10 H).
fast exchange limit, 95C:
8 1.70 (s, 6 H), 1.81 (s, 2 H), 5.51 (bs, 4 H), 5.85 (bs, 4 H) 7.00-7.49 (m,
10 H).
Calculation of free activation energy, AG:
two Cp resonances are separated by 0.60 ppm at slow exchange limit and at 300 MHz
85
AS = 6.10-5.50 = 0.60 ppm (300 MHz) = 180 Hz
and thus, at the coalescence temperature (600 C)
k
x (180 s' l)
(AS)
42
42
The Eyring equation gives the relationship of the rate constant to AG
k = (T/h) e-AG /RT
thus,
AG = -RT[ln (kT) + In (h/i)]
where
R = 1.987 x 10-3kcal/mol-K
ic = Boltzmann's constant = 1.38054 x 10-16erg/k
h = Planck's constant = 6.6256 x 10-27 erg-sec
T = temperature in K
thus, for complex 9
AG = 15.6 kcal/mol
I
I
Preparation of CpZrCH2C(=CHz)O,
10 (TW-II-33, IV-4, V-4)
A yellow ether solution of the dianion 6b derived from 0.91 mL (12.5 mmol) of
acetone was added dropwise to a solution of 3.64 g (12.5 mmol) of Cp2 ZrC2 in 100 mL
of THF under N2 at -780 C (eq. 3). The resulting mixture was allowed to warm slowly to
room temperature and was stirred overnight. An yellow suspension was obtained. All
volatiles were removed at reduced pressure, and the residue was extracted with 3 x 100 mL
of toluene. Filtration through Celite was followed by concentration of the yellow filtrate to
86
about 30 mL and addition of 150 mL of hexane. The resulting off-white precipitate was
washed twice with hexane and then dried in vacuo. A fine off-white solid, 10, 1.7 g
(50%), was obtained. Analytically pure samples were obtained by recrystallization from
dichloromethane, mp 150-153 0 C dec.
1H
NMR (300 MHz, C6 D6 ):
1.61 (s, 2 H), 3.69 (s, I H), 3.84 (s, 1 H), 5.76
(s, 10 H).
1 3C
NMR (75.4 MHz, CDC13): 8 32.9 (t, J = 131 Hz, CH2 ), 79.4 (t, J = 158 Hz,
C=CH 2 ), 109.9 (d, J = 178.0 Hz, C 5 H 5 ), 172 (t, 2J = 6.0 Hz, C---CH2 ).
MS (EI, 9 OZr) Calcd. for C2 6 H28Zr20
2:
552; Found: m/z (fragment, relative intensity):
552 ( 2M+ , 5), 512 (2M+ - CH2 C=CH 2, 25), 487 (2M+ - Cp, 4), 447 (10),
389 (18), 342 (17), 276 (M+, 26), 236 (Cp2Zr=O, 12), 220 (Cp2Zr, 42), 65
(Cp), 40 (CH2CCH2, 81),
IR ( KBr, cm-1): 3093(w), 2960(w), 2899(w), 1709(w), 1622(s), 1530(w), 1443(w),
1365(w), 1282(w), 1222(s), 1018(m), 948(m), 917(w), 811(s), 762(s),
710(m).
Anal. Calcd. for C2 6 H2 8 Zr2 02 : C, 56.27; H, 5.10. Found: C, 56.05; H, 5.11.
Variable-temperature
1H
NMR (toluene - d8 , 300 MHz,):
slow exchange limit, -70°C:
8 1.45 (d, J = 10 Hz, 1 H), 1.60 (d, J = 10 Hz, 1 H), 3.75 (s, 1 H), 4.00
(s, 1 H), 5.67 (s, 5 H), 5.68 (s, 5 H).
coalescence temperature, -57°C:
87
8 1.43 (br s, 1 H), 1.58 (br s, 1 H), 3.72 (s, 1 H), 3.98 (s, 1 H), 5.67 (s, 10
H).
fast exchange limit, -100 C:
8 1.55 (s, 2 H), 3.67 (s, 1 H), 3.82 (s, 1 H), 5.71 (s, 10 H).
Calculation of free activation energy, AG:
two Cp resonances are separated by 0.01 ppm at slow exchange limit and at 300 MHz
A8 = 5.68-5.67 = 0.01 ppm (300 MHz) = 3 Hz
and thus, at the coalescence temperature (-570 C)
k=
sI(AS)
k=
=
l2
(3s ' )
~]2
= 6.7
s
The Eyring equation gives the relationship of the rate constant to AG
k = (T/h)
e-a G/RT
thus,
AG = -RT[ln (k/T) + In (h/c)]
where
R = 1.987 x 10-3 kcal/mol K
K
= Boltzmann's constant = 1.38054 x 10- 16 erg/k
h = Planck's constant = 6.6256 x 10-27 erg-sec
T = temperature in K
thus, for complex 10
AG = 11.7 kcal/mol
88
I
I
Preparation of CpzHfCH 2C(=CH2)O, 11 (TW.IV.40,
V-13)
A yellow ether solution of the dianion 6b derived from 0.91 mL (12.5 mmol) of
acetone was added dropwise to a solution of 4.72 g (12.5 mmol) of Cp2 HfCI 2 in 100 mL
of THF under N2 at -78C (eq. 3). The resulting mixture was allowed to warm slowly to
room temperature and was stirred overnight. An yellow suspension was obtained. All
volatiles were removed at reduced pressure, and the residue was extracted with 3 x 100 mL
of toluene. Filtration through Celite was followed by concentration of the yellow filtrate to
about 30 mL and addition of 150 mL of hexane. The resulting off-white precipitate was
washed twice with hexane and then dried in vacuo. A fine off-white solid, 11, 2.2 g
(48%), was obtained, mp 203-204°C. Our attempts to obtain analytically pure samples by
repeated recrystallization from a variety of solvents (toluene, methylene chloride, ether)
have been unsuccessful.
1H
NMR (300 MHz, C 6 D 6 ):
1.37 (s, 2 H), 3.72 (s, 1 H), 3.74 (s, 1 H), 5.80 (s, 10
H).
13 C
NMR (75.4 MHz, CDC13): 8 48.2 (t, J = 120 Hz, CH2 ), 79.5 (t, J = 158 Hz,
C=CH 2 ), 110.6 (d, J = 178 Hz, C5 H5), 176.2 (t, 2J = 4 Hz, CH2 C=CH2).
MS (EI,
180 Hf) Calcd.
for C26 H28Zr2 02 : 732; Found: m/z (relative intensity): 732 ( 2M+,
4), 692 (2M + - CH 2 C--CH 2 , 24), 667 (2M + - Cp, 4), 566 (15), 366 (M+, 15), 326
(Cp2Hf=O, 30), 310 (Cp2Hf, 15), 259 (9),106 (5), 65 (Cp, 36), 40 (CH2CCH2,
48).
89
IR ( KBr, cm-l): 3078(w), 2953(w), 2889(w), 1699(w), 1616(s), 1524(w), 1436(w),
1363(w), 1278(w), 1221(s), 1015(m), 986(s), 939(m), 909(w), 809(s),
758(s), 704(m), 689(m).
Anal. Calcd for C2 6 H28 Hf2 02 : C 42.81; H, 3.87. Found: C, 40.99; H, 3.51
Variable-temperature
1H
NMR (toluene - d8 , 300 MHz,):
slow exchange limit, -78.5°C:
6 1.16 (d, J = 10 Hz, 1 H), 1.43 (d, J = 10 Hz, 1 H), 3.87 (s, 1 H), 3.94
(s 1 H), 5.67 (s, 5 H), 5.84 (s, 5 H).
coalescence temperature, -58.5°C:
6 1.32 (br s, 2 H), 3.82 (s, 1 H), 3.87 (s 1 H), 5.75 (br, s, 10 H)
fast exchange limit, -18.4C:
8 1.31 (s, 2 H), 3.72 (s, 1 H), 3.74 (s 1 H), 5.77 (s, 10 H),
Calculation of free activation energy, AG:
two Cp resonances are separated by 0.17 ppm at slow exchange limit and at 300 MHz
AS = 5.84-5.67 = 0.17 ppm (300 MHz) = 51 Hz
and thus, at the coalescence temperature (-58.5°C)
k= -
(S)
2
x (51 s)
= 113.3 g t
2
The Eyring equation gives the relationship of the rate constant to AG
90
k = (cT/h) e-AG/RT
thus,
AG = -RT[ln (kr) + In (h/ic)]
where
R = 1.987 x 10-3 kcal/mol-K
= Boltzmann's constant = 1.38054 x 10-16erg/k
h = Planck's constant = 6.6256 x 10-27erg-sec
T = temperature in K
thus, for complex 11
AG = 10.4 kcal/mol
I
Preparation of (PPh 3 )PtCH 2 C(=O)CH2
17(TW-IV-61,
65, 70)
An Et2 0 solution of 2.5 mmol of the acetone dianion 6b was added dropwise to
one molar equivalent of (Ph3 P)2PtC 2 (1.97 g, 2.5 mmol) in 50 mL of Et2 O under N2 at 78°C (eq. 1). The resulting mixture was warmed slowly to room temperature and stirred
overnight. A pale yellow suspension resulted which was filtered under nitrogen through
Celite to give a clear yellow solution. The filtrate was concentrated to about 20 mL under
reduced pressure and added to 100 mL of pentane. A pale yellow precipitate resulted. The
latter was washed twice with pentane and then dried in vacuo. A fine, pale yellow solid,
16, 0.9 g (45%) was isolated, mp 187-189°C dec.
1H
NMR (300 MHz, CDC13):
2.31 (br, 4 H, J (PtH) = 46.8 Hz)), 7.08-7.70 (m, 30
H).
13 C {1 H
NMR (75.4 MHz, CDC13):
50.4 (d, CH2 C(O)CH2, J (CP) = 54 Hz, J
(CPt) = 242 Hz), 125-140 (m, Ph), 179.6 (s, CH2 C(O)CH 2 ).
91
31p
{1 H) NMR (121.4 MHz, CDC13 ): 8 23.4 (s, J (PtP) = 2960.5 Hz)
IR ( KBr, cm-1): 3051(w), 2958(m), 2928(w), 1590(w), 1545(s, C=O), 1479(s),
1434(w), 1183(w), 1095(w), 1027(w), 902(m), 894(w), 865(w).
1H, 13 C
and 3 1p NMR, IR and mp data obtained by Kemmitt and coworkers8 are as
follow:
1H
NMR (400 MHz, CD2 C12): 8 2.65 (br m, 4 H, J (PtH) = 45.6 Hz)), 7.0-7.7 (m, 30
H, Ph).
13 C {1 H
NMR (75.4 MHz, CD2 C12 ):
49.9 (d, CH2 C(O)CH 2, J (CP) = 54 Hz, J
(CPt) = 242 Hz), 125-140 (m, Ph), 183.8 (s, CH2C(O)CH2).
31p
{1H) NMR (22.4 MHz, CD2C12 ): 8 22.4 (s, J (PtP) = 3085 Hz)
mp: 190°C
IR (CsCI, cm-1): 1535 (C=O)
I!
Reaction of Cp2rCH 2C(=CPh2)O, 7 with HCI (TW-VI-10).
A 15 mg sample of 7' was placed in a 5-mm NMR tube along with 0.4 mL of
C6 D6 The tube was placed on a vacuum line under N2 . An excess of anhydrous HC1was
bubbled into the tube. The color of the solution changed from yellow to pale yellow. The
products, as determined by 1H NMR, were zirconocene dichloride (the only Zr-containing
product) and 1,1-diphenyl-2-propanone, Ph2 CHC(O)CH3 , by comparison to an authentic
sample.
92
Attempted Reaction of 1,1-Diphenylacetone Dianion [Ph2 CC(O)CH 2 ] 2 '
with Cp2TiCI2 (TW-III-43,
IV-13)
A red THF solution of the dianion 6a derived from 2.62 g (12.5 mmol) of 1,1diphenyl-2-propanone was added dropwise to a solution of 3.10 g (12.5 mmol) of
Cp2 TiC12in 100 mL of THF solution under N2 at -780 C. The resulting mixture was
allowed to warm slowly to room temperature and was stirred overnight. The resulting deep
red suspension was evaporated at reduced pressure. The residue was extracted with 3 x
100 mL of toluene. Filtration through Celite was followed by concentration of the deep red
filtrate to about 20 mL and addition of 150 mL of hexane. The resulting red precipitate was
washed twice with hexane and dried in vacuo (3.4 g). The 1 H NMR spectrum (Figure
28) of the crude products indicated the presence of the expected 2-titanaoxacyclobutanes,
but the presence of impurities in large amounts prevented their isolation. Attempts to obtain
a pure product by recrystallization from a variety of solvents (toluene, dichloromethane,
chloroform, toluene/hexane, dichloromethane/hexane and ether/hexane) have not been
successful.
1H
NMR spectrum (300 MHz, C6D6)of the crude product
1.91 (d, J = 10 Hz), 2.11 (s), 2.39 (s), 2.55 (d, J = 10 Hz), 5.43 (s), 5.85 (s), 5.89 (s),
7.0-7.6 (m)
1H
NMR spectrum (90 MHz, C6 D6 ) of 2-titanaoxacyclobutane, 15, reported by
Grubbs1 2
1.91 (d, J = 10 Hz, 1 H), 2.54 (d, J = 10 Hz, 1 H), 5.44 (s, 5 H), 5.89 (s, 5 H), 7.26 (m
10 H)
93
C_ -
0
C)
C
_
cu
.
E-4
_
_w
In
_
Om
Q.
r
_
v-
I:
0
Z
F.
·0
wi
-
I
C
_o
_
94
Attempted Reaction of 1,1-Diphenylacetone Dianion [Ph2 CC(O)CH 2 ] 2 with Cp*2ZrCI2 (TW-H-43, 52)
A red THF solution of the dianion 6a derived from 1.31 g (6.25 mmol) of 1,1diphenyl-2-propanone was added dropwise to a solution of 2.70 g (6.25 mmol) of
Cp*2 ZrC12 in 100 mL of THF solution under N2 at -780 C. The resulting mixture was
allowed to warm slowly to room temperature and was stirred overnight. The resulting
orange suspension was evaporated at reduced pressure. The residue was extracted with 3 x
100 mL of hexane. Filtration through Celite was followed by concentration of the orange
filtrate to about 30 mL. An orange solid, 2.5 g, was obtained after crystallization from
hexane at -23°C. A complexity of the resonances at 2.00 ppm in 1 H NMR spectrum
(Figure 29) likely indicates that the dianion 1 attacked the methyl groups of the Cp*
ligands. A complex product mixture was obtained from the reaction of Cp*2ZrCI2with the
dianion
1.
I
I
Attempted Reaction of Cp2ZrCHzC(=CPh2 )O, 7 with CO (TW-V-46)
A 50 mL flask was charged with 0.25 g (0.58 mmol) of 7' dissolved in 20 mL of
toluene. To the stirred solution was added excess of dry CO. After stirring for 20 min at
room temperature, the solvent was removed under reduced pressure. The products, as
determined by 1H NMR spectrum, were starting material 7.
~~~~I
~~I1
Attempted Reaction of Cp2ZrCH2C(=CPh2 )O, 7 with (O=CHZ)n (TW-V-48)
A 50 mL flask was charged with 0.25 g (0.58 mmol) of 7' dissolved in 20 mL of
toluene. To the stirred solution was added 0.09 g (3 mmol) of paraformaldehyde under an
argon counterflow. After stirring overnight at room temperature, the solvent was removed
under reduced pressure. The products, as determined by 1H NMR spectrum, were starting
materials.
95
es
c
o
tq
sr
Qu
I,eq
0o
eq
0
ai
.u
ad
U.
cr
0;
to
SW
1"4
96
I
I
Attempted Reaction of Cp2 ZrCH2 C(=CPh2)O, 7 with O=CHPh (TW-IV-11,
31)
Method A.
A 50 mL flask was charged with 0.25 g (0.58 mmol) of 7'
dissolved in 20 mL of toluene. To the stirred solution was added 0.31 mL (3 mmol) of
benzaldehyde by syringe. After stirring overnight at room temperature, the solvent was
removed under reduced pressure. The products, as determined by 1 H NMR spectrum,
were starting materials.
Method B.
A glass tube was charged with 0.1 g (0.23 mmol) of 7' dissolved in
10 mL of toluene. To the toluene solution of 7 was added 50 pL (0.49 mmol) of
benzaldehyde by syringe. The tube then was sealed under vacuum. After heating
overnight at 80°C, the solvent was removed under reduced pressure. The products, as
determined by 1H NMR spectrum, were starting materials.
I
I
Attempted Reaction of Cp2ZrCHC(=CPh 2 )O, 7 with HC-CPh
(TW-III-22,
40)
Method A.
A 50 mL flask was charged with 0.25 g (0.58 mmol) of 7'
dissolved in 20 mL of toluene. To the stirred solution was added 0.33 mL (3 mmol) of
HC- CPh by syringe After stirring overnight at room temperature, the solvent was
removed under reduced pressure. The products, as determined by 1H NMR spectrum,
were starting materials.
Method B.
A glass tube was charged with 0.1 g (0.23 mmol) of 7' dissolved in
10 mL of toluene. To the toluene solution of 7 was added 55 I.L (0.49 mmol) of
phenylacetylene by syringe. The tube then was sealed under vacuum. After heating
overnight at 100°C, the solvent was removed under reduced pressure. The products, as
determined by 1H NMR spectrum, were starting materials.
97
Attempted Reaction of CpzZrCH2C(=CPh2)0, 7 with t-BuNC (TW-IV-6)
Method A.
A 50 mL flask was charged with 0.25 g (0.58 mmol) of 7'
dissolved in 20 mL of toluene. To the stirred solution was added 0.25 g (3 mmol) of tBuNC by syringe. After stirring overnight at room temperature, the solvent was removed
under reduced pressure. The products, as determined by 1H NMR spectrum, were starting
materials.
Method B.
A glass tube was charged with 0.1 g (0.23 mmol) of 7' dissolved in
10 mL of toluene. To the toluene solution of 7 was added 57 tL (0.5 mmol) of tert-butyl
isocyanide by syringe. The tube then was sealed under vacuum. After heating overnight at
100°C, the solvent was removed under reduced pressure. The products, as determined by
1H NMR spectrum,
were starting materials.
I
I
Attempted Reaction of Cp2ZrCH2 C(=CPh 2)O, 7 with Et-NC (TW-V-45)
A 50 mL flask was charged with 0.25 g (0.58 mmol) of 7' dissolved in 20 mL of
toluene. To the stirred solution was added 0.17 g (3 mmol) of ethylisocyanide by syringe.
After stirring overnight at room temperature, the solvent was removed under reduced
pressure. The products, as determined by 1 H NMR spectrum, were starting materials.
r
I
Mass Spectra of compound Cp2 TiCH2 C(=CPh2 )O, 15
Compound 15 was synthesized by the method reported by Grubbs and
coworkers. 12 EI and FAB mass spectra of 15 were shown in Figure 30-32
MS (EI, 48 Ti) Calcd. for C50H44Ti2 0 2: 772; Found: m/z (relative intensity): 772 ( 2M+,
1), 594 (2M+ - Cp2Ti, 7), 529 (2M+ - Cp2Ti - Cp, 16), 386 (M+ , 9), 321 (M+ Cp, 5), 192 (Ph2CCCH2, 37), 178 (Cp2Ti, 100), 165 (17), 129 (10), 113 (22),
65 (Cp, 6)
98
MS (FAB,
4 8 Ti)
2, 3)
Calcd. for C50H44Ti2 0 2 : 772; Found: m/z (relative intensity): 774 (M+ +
99
v}
-6
,E-
A
O
u04
U
-Es
S..
100
(M
cn- -
r'I
tn
u"
do
4
-
vlW
r~
U
L.Dr
(M
r"
-
-I
0
co
cajm
r
-=t L
0
uv
crn
LDr
-
0v
O
Ln-
-
fn
rl
SW
I
LJ)
Ln
m
'
I
I
I
101
l
LO
rn
cu
II
u
-4
-
L.
0
ts
CND
U,
20
96
LO
Z
Cf
r
I
I
m.
04
elo u
c
Cs
o, LOCUD
C
,AJ
rf
(4
en
N
.-. :2EU .
·--"
Lot
-m
m
Pk
mt
I l,
.
.
Iw
.
,
cJ
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---(
Ln 0 cm
102
REFERENCES
1.
Jones, M. D.; Kemmitt, R. D. W. Adv. Organomet. Chem 1987, 27, 279.
2.
(a)
Grosselin, J. M.; Dixneuf, P. H. J. Organomet. Chem. 1986, 314, C76
(b)
Mills, N. S.; Lokey, R. S.; Rheingold, A. L. Organometallics 1989, 8,
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Trimitsis, G. B.; Hinkley, J. M.; TenBrink, R.; Poli, M.; Gustafson, G.;
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Bays, J. P. J. Org. Chem 1978, 43, 38.
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Hubbard, J. S.; Harris, T. M. J. Am. Chem. Soc. 1980, 102, 2110.
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Thompson, C. M.; Green, D. L. C. Tetrahedron 1991, 25, 4223 (general
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6.
Kos, A. J.; Clark, T.; Schleyer, P. v. R. Angew. Chem. Int. Ed. Engl.
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7.
Chiu, K. W.; Henderson, W.; Kemmitt, R. D.W.; Prouse, J. S.; Russell, D. R. J.
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(a)
Jones, M. D.; Kemmitt, R. D. W.; Fawcett, J. Russell, D. R. J. Chem. Soc.,
Chem. Commun. 1986, 427.
(b)
Fawcett, J.; Henderson, W.; Jones, M. D.; Kemmitt, R. D. W.; Russell, D.
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Sandstrom, J. Dynamic NMR Spectroscopy, Academic Press: London/New York,
1982.
10.
(a)
Erker, G.; KrUger, C.; Miller, G. Adv. Organomet. Chem. 1985, 24, 1.
(b)
Kruger, C.; MUller, G.; Erker, G.; Dorf, U.; Engel, K. Organometallics
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11.
Hartwig, J. H.; Anderson, R. A. Bergman, R. G. J. Am. Chem. Soc. 1990,
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Ho, S. C.; Hentges, S.; Grubbs, R. H. Organometallics
13.
(a)
Jorgensen, K. A.; Schiott, B. Chem Rev. 1990, 90, 1483.
(b)
Sharpless, K. B.; Teranishi, A. Y.; Bickvall, J. E. J. Am. Chem. Soc.
1977, 99, 3120.
(c)
Collman, J. P.; Kodadek, T.; Raybuck, S. A.; Brauman, J. I.; Papazian, L.
M. J. Am. Chem. Soc. 1985, 107, 2000.
104
(d)
Groves, J. T.; Avaria-Neisser, G. E.; ; Fish, K. M.; Imachi, M.;
Kuczkowski, R. L. J. Am. Chem. Soc. 1986, 108, 3837.
14.
(e)
Milstein, D.; Calabrese, J. C. J. Am. Chem. Soc. 1982, 104, 3773.
(a)
Bazan, G. C.; Schrock, R. R.; O'Regan, M. Organometallics,
1991, 10,
1062
(b)
Whinnery, L. L.; Henling, L. M.; Bercaw, J. E. J. Am. Chem. Soc. 1991,
113, 7575.
15.
Tikkanen, W. R.; Petersen, J. L. Organometallics 1984, 3, 1651.
16.
(a)
Erker, G.; Hoffmann, U.; Zwettler, R.; Betz, P.; Kruger, C. Angew. Chem.
Int. Ed. Engl. 1989, 28, 630.
(b)
Erker, G.; Hoffmann, U.; Zwettler, R.; Kriiger, C. J. Organomet. Chem
1989, 367, C15.
17.
Bristow, G. S.; Hitchcock, P. B.; Lappert, M. F. J. Chem. Soc., Chem.
Commun. 1982, 462
18.
(a)
Erker, G.; Mena, M.; Krfiger, C.; Noe, R. Organometallics
1991, 10,
1201.
(b)
Erker, G.; Mena, M.; Kriiger, C.; Noe, R. J. Organomet. Chem. 1991,
402, 67.
19.
(a)
Yamakawa, M.; Mashima, K.; Takaya, H. J. Chem. Soc., Dalton Trans.
1991, 2851.
(b)
Takaya, H.; Yamakawa, M.; Mashima, K. J. Chem. Soc., Chem. Commun.,
1983, 1283.
20.
Vaughan, G. A.; Hillhouse, G. L.; Lum, R. T.; Buchwald, S.; Rheingold, A. L.
J. Am. Chem. Soc. 1988, 110, 7215.
21.
Gardin, D. J.; Lappert, M. F.; Raston, C. L., Chemistry of Organozirconium andHafnium Compounds; Ellis Horwood Ltd: West Sussex, 1986, p 228.
105
22.
(a)
Erker, G.; Engel, K.; Atwood, J. L.; Hunter, W. E.; Angew. Chenm.Int.
Ed Engl. 1983, 22, 494.
(b)
Kai, Y.; Kanehisa, N.; Miki, K.; Kasai, N.; Akita, M.; Yasuda, H.;
Nakamura, A. Bull. Chem Soc. Jpn. 1983, 56, 3735.
23.
(a)
Erker, G.; Dehnicke, S.; Rump, M.; KrUiger, C.; Werner, S.; Nolte, M.
Angew. Chem. Int. Ed. Engl. 1991, 30, 1349.
(b)
Erker, G.; Rump, M.; KrUger,C.; Nolte, M. Inorg. Chin. Acta 1992, 198,
679.
24.
Slater, J. C.; J. Chem Phys. 1964, 41, 3199.
25
Allen, F. H.; Kennard, O.; Watson, D. G.; Brammer, L.; Orpen, A. G.; Taylor, R.
J. Chem Soc., Perkin Trans. 1987, 2, 51-519
26.
Vaughan, G. A.; Hillhouse, G. L.; Rheingold, A. L. J. Am. Chem. Soc. 1990,
112, 7994.
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28.
Hubbard, J. Tetrahedron 1988, 29, 3197.
29.
DIFABS:
30.
Structure Solution Methods:
Mithril:
Walker, H.; Stuart, D. Acta Cryst. 1983, A39, 158.
Mithril - an integrated direct methods compputer program. Gilmore,
C. J. J. Appl. Cryst. 1984, 17, p 43. University of Glasgow,
Scotland.
DIRDIF:
DIRDIF - Direct Methods for Difference Structures - an automatic
procedure for phase extension and refinement of difference structure
factors. Beurskens, P. T. Technical Report 1984/1 Crystallography
Laboratory, Toernooiveld, 6525 Ed Nijmegen, Netherlands.
31.
Least-Squares:
Function minimized:
where:
Iw(IFol - IFcI)2
w = 4Fo2 /a 2 (Fo2 )
106
a 2 (Fo 2 ) = [S2 (C+R 2 B) + (pFo2 )2 ]/Lp2
S = Scan rate
C = Total integrated peak count
R = Ratio of scan time to background counting time
B = Total background count
Lp = Lorentz-polarization factor
p = p-factor
32.
Standard deviation of an observation of unit weight:
[1w(Fol - IFcl)2 /(No- Nv)]1/2
where:
No = number of observations
Nv = number of variables
33.
Cromer, D. T.; Waber, J. T. in International Tablesfor X-ray crystallography;
Ibers, J. A.; Hamilton, W. C., Eds.: Kynoch Press: Birmingham, 1974; Vol.
IV, Table 2.2a.
34.
Ibers, J. A.; Hamilton, W. C. Acta Crystallogr. 1964, 17, 781.
35.
ref. 30, Table 2.3.1.
36.
TEXSAN - TEXRAY Structure Analysis Package, Molecular Structure
Corporation, 1985.
107
CHAPTER TWO
Reactions of Organosilicon Halides with the Ambident l,1-Diphenylacetone Dianion
108
INTRODUCTION
In research reported in chapter 1, we found that dianions of type [CH2 C(O)CR2]2 (R = Ph, H), can be ambident in their reactions with metal dihalides. Dianions 1 and 2
O a'- -
O
a2,
R2 C0'
"CR2
m1
1 R=Ph
2 R=H
react with the oxophilic bis(cyclopentadienyl) dichlorides of zirconium and hafnium as C,
O dinucleophiles, giving 1,5-dimetalla-2,6-dioxa-3,7-dimethylenecyclooctanes,3, which
appear to dissociate in solution to form 2-metallaoxa-3-methylenecyclobutanes.
Cp\ /Cp
R
OM
C=C
R
CC
H 2 CMO
Cp
R
CH2
R
Cp
3 M = Zr, Hf
In contrast, the dianion 2 (R = H) reacts with cis-bis(triphenylphosphine) platinum
dichloride as a C, C-dinucleophile, giving a 3-metallacyclobutanone, 4 (M = Pt, R = H).1
Earlier studies of Kemmitt and coworkers had shown that with cis-[L2PtC12]and trans-
109
[L2 PdCI2] complexes the dianion derived from dibenzyl ketone reacted as a C, C-
dinucleophile, giving similar products 4.2
Ph3P\
H.0 R
. C
Ph3P M-,,\
H
C
R
4 M = Pt, Pd
Since silicon is oxophilic in nature, it was expected that the acetone dianions would
react with dihalosilanes, R2SiX2, as C, O-dinucleophiles in a manner similar to the
reactions with zirconium and hafnium. The results of these experiments will be reported in
this chapter.
110
RESULTS AND DISCUSSION
1,1-Diphenylacetone dianion 1,3 prepared from l,l-diphenylacetone,
and
successively, one equivalent of KH, and one equivalent of n-BuLi, reacts readily with
dimethyldichlorosilane, methyldichlorosilane, diethyldichlorosilane and
diphenyldichlorosilane at 0°C in THF to give 8-membered cyclic products 5, 6, 7 and 8
in 40-70% yield (Eq. 1). In view of the products of the [Ph 2CC(O)CH 2-/(T
]2
5-
CsHs)2MC12(M = Zr, Hf) reaction, 3, the formation of these products was surprising, and
we shall return to this point later in the discussion. Compounds 5, 6, and 7 were purified
by recrystallization from hexane, and compound 8 was purified by recrystallization from
R1
0
PhC'
RR"CPh
'CH
2
0RI
,R 2
Sii,R
5 R_=R2=Me
Ph_
C=C
H2 CX.Si
Ph
C 6 R_=R2=Et 1h
R1 =R 2 =Me
=R22 =Ph
=PEt
75Ri=Me,
R 2 H CH2 68 RR1 =R
methylene chloride and hexane. Compounds 7 and 8 were difficult to redissolve in hexane
after recrystallization. However, compounds 7 and 8 are quite soluble in chlorinated
solvents, benzene, toluene, and THF. Compounds 5 and 6 are quite soluble in hexane,
chlorinated solvents, benzene, toluene, diethyl ether, and THF.
The use of higher reaction temperatures decreases the yield of product, but lower
reaction temperatures do not increase the yield. It is likely that the dianion slowly attacks
THF at the higher temperatures.4 The yields of the reactions decrease as the size of the
substituents on the silicon atom increases. In the reaction of 1 with methyldichlorosilane,
111
the yield of product 7 is higher ( 70%) than the yield of product 8 (40%) from the reaction
of 1 with diphenyldichlorosilane.
2
The low yield of the [Ph 2 CC(O)CH 2 ]-/Ph
2SiCI2
reaction could be the result of competitive attack of the 1,l-diphenylacetone dianion 1 on
the THF solvent due to the slow reaction of the more sterically hindered Ph2SiCl2 with the
1,-diphenylacetone
dianion. Attempts to react 1 with di-t-butyldichlorosilane were
unsuccessful. This may be a result of steric constraints. The bulky nature of the t-Bu
groups probably prevents attack of dianion 1 at silicon. The rate of attack by 1 as well as
the yields obtained, depended on steric factors in the chlorosilane - the reaction of 1 with
dimethyldichlorosilane and methyldichlorosilane occurred at a faster rate and with higher
yields than the reaction of 1 with diphenyldichlorosilane.
The reactions of the 1,l-diphenylacetone dianion 1 with diethyldifluorosilane and
diphenyldifluorosilanealso were carried out under similar conditions. It was immediately
apparent that the white crystals isolated in 47% and 21% yield, respectively, were not the
expected 6 and 8 since their melting points were different. Combustion analysis, however,
established the same elemental composition and the EI mass spectrum indicated a "dimeric"
formulation. Surprisingly, the products, compounds 9 and 10, are the positional isomers
of 6 and 8, respectively, ( Eq. 2). The reactions of dianion 1 with diethyldifluorosilane
and diphenyldifluorosilane are much slower than those with the corresponding
diorganodichlorosilanes. The red color of 1 did not disappear even after stirring at room
temperature for three days.
112
<32SiF2
R
Ph2 C
CH 2
CsH2
p
h
Ph2
2C
S
/
(2
CPh
Rh
HSi"
9 R=Et
10 R =Ph
In the reaction of dianion 1 with diphenyldifluorosilane, a yellow oligomeric
mixture (2.5 g), which is soluble in hexane, also was obtained in addition to compound
10. This oligomeric mixture has a molecular weight ranging from 500 to 2400, as
determined by GPC using polystyrene standards. The 29 Si NMR spectrum of this
oligomeric mixture shows five silicon signals, which could not be assigned.
A ten-membered cyclic compound 11 and a six-membered cyclic compound 12
also were prepared by similar reactions of dianion 1 with 1,2-dichlorotetramethyldisilane
and 1,3-dichlorohexamethyltrisilane ( Eq. 3 ). Compounds 11 and 12 were obtained in
67% and 62% yield, respectively. A twelve-membered cyclic product was not isolated in
the reaction of 1 with 1,3-dichlorohexamethyltrisilane.
It appears that the six-membered
cyclic compound is quite stable in terms of ring strain and can therefore be readily formed.
Compounds 11 and 12 are soluble in common organic solvents such as hexane, benzene,
and chloroform. Compounds 5-12 are colorless, air-stable solids which can be handled
without any special precautions.
113
Me2Me 2
Si- Si
Ph
CSiMe
2 SiMe 2 Cl
,
Ph/
O
Si-
/
Ph
/
r M-.- r ~r
H'CH
,CH
2
Ph
2
Si- Si
le21*2
0
.
11
O
(3)
Ph2 C'
'CH
2
CIMe2SiMe
2
1
CMe
2 SiMe 2SiSiMe 2C
Si
SiMe 2
IO~
I
6
CH2
II
C
Ph/
Ph
12
Compounds 5-12 were fully characterized using 1 H, 13C,and
29 Si NMR
spectroscopy, IR spectroscopy, mass spectroscopy, elemental analysis and vapor pressure
osmometry. The structures of compounds 8, 10, and 11 were confirmed by X-ray
diffraction studies. The yields, melting points and the results from elemental analyses are
given in Table 1.
114
Table 1. Physical properties of 5-12
compound yield
mp
analysis: % calculated/found
C
H
(o C)
5
69
145-147
6
8
56
70
47
9
41
10
21
84-86
239-240
11
67
62
132-134
94-96
7
12
6.81/7.03
110-112
76.64/76.60
77.49/77.40
180-182
76.14/75.99
6.39/6.45
189-191
83.03/82.72
77.49/77.39
5.68/5.76
7.55/7.55
83.03/82.79
70.31/70.27
7.55/7.58
5.68/5.72
7.45/7.46
65.90/66.03
7.90/7.91
The eight-membered rings can have one of two structures: A or B (Figure 1).
Structure A has two chemically different silicon atoms. There would be two different
signals in the 29 Si NMR spectrum and two different sets of signals for the R substituents
on the silicon atoms in the 1H and
13C
NMR spectra. The silicon atoms in structure B are
chemically equivalent. There would be only one signal in the
2 9 Si
signal for the R substituents on the silicon atoms in the 1H and
NMR spectrum and one
13 C
NMR spectra.
R
Ph\
Ph
°/
Ph
Si
Ph
C- C
c= C
Ph
o
_r
H14.
R
R
A
DP
rl
Ph/
C
H2C_ Si..
R'
Ph
R
B
Figure 1. Two possible structures for eight-membered ring
The 1 H NMR spectral data for 5-12 are given in Table 2. In the 1 H NMR spectra
of 5-12, each of the compounds exhibits a characteristic singlet resonance for the
115
methylene, -CH2- group except compound 7. The 1 H NMR spectra of 5 (Figure 2) and
6 (Figure 3) show two types of SiMe and SiEt groups, respectively. The 1 H NMR
spectrum of 9 (Figure 4) shows only one type of SiEt group. This would suggest that 5
and 6 have structure A, and 9 has structure B. The 1H NMR spectrum of 12 shows three
different types of SiMe groups in the range of 0.08 to 0.19 ppm which would be expected
from the six-membered ring structure. It is impossible to determine the structures of
compounds 8 and 10 from the 1 H NMR spectra because the chemical shift difference for
the -CH2- groups is only 0.06 ppm.
In the 1H NMR spectrum of 7, interesting splitting patterns are observed for the
methylene protons in the ring (Figure 5). The methylene protons appear as a doublet and
a doublet of doublets at 2.18 and 2.05 ppm, respectively. The primary two doublets show
a typical AB splitting pattern which can be attributed to a slight chemical difference between
the axial and equatorial protons, Ha and Hb (Figure 6). These two protons couple with
each other to give two doublets. The primary coupling constant is 2 Jab= 14.2 Hz. The
secondary doublet is the result of coupling to the Si-H proton (3 J = 4.0 Hz). Only trans
secondary coupling is observed; cis coupling is too small. This gives rise to the doublet
splitting pattern. The 1 H NMR spectrum of 7 also shows signals due to two types of SiMe
groups and two different types of Si-H protons. All the SiMe protons appear as doublets
due to coupling to the Si-H protons. The coupling constants are 3J = 3.6 and 1.5 Hz,
respectively. One Si-H appears as a broad signal at 4.05 ppm, which corresponds to
(-CH2)2SiHCH3. Another Si-H is observed as a doublet at 4.65 ppm, which corresponds
to -O2 SiHCH3. The doublet (3 J = 1.5 Hz) is a result of coupling to the protons of the
terminal CH3 groups. While the CH3 coupling should result in a quartet splitting pattern,
the quartet was not fully resolved and only the central, more intense peaks of the quartet
were observed, giving rise to the doublet splitting pattern.
116
i
0
924
pr
..
WA
117
I
I
I
:
0
a
- I oo
b
C,
-
i
-> a
PL
118
-o
r
_
O
E
0
Ft.
2
SW
ga,
V'J
E
Z
ll
__rl
7 _
7
-
h;
119
xk
a.
Q
-I
a
L I1 !
I.la
E °J
asr
,.a
i
tI
_
-5g
o r.
m
a0
m
c)
I
Us
rA
0
t)*
e
-J
I..
;T
aI
(a
120
Ph
0
0
\
M/
h/
Ph
H
M
/
Me,.
Figure 6. Compound 7
The 13CNMR spectral data for 5-12 are given in Table 3. The data are consistent
with the results from the 1 H NMR spectra. All the compounds show characteristic triplet -
CH2 - carbon signals in the 13 C NMR spectra. No carbonyl carbon peaks are observed in
the 13 C NMR spectra. This provides clear evidence that dianion 1 reacts with
organosilicon dihalides as a C, O - dinucleophile. Compounds 5 and 7 exhibit two distinct
SiMe carbon signals in the
13C
NMR spectra, representing two different SiMe groups in
each compound. This supports the structure A for compounds 5 and 7. For 6 (Figure
7), two different sets of SiEt carbon resonances are observed, indicating that compound 6
also has structure A. For 9 (Figure 8), only one set of SiEt carbon resonances is
observed, indicating that compound 9 has structure B.
121
o
a
w
0
2tal
I
0~
U)
m
W
9
7.
zIS-
*
en
so
0
w
wo·
122
i
-o
I
0t
a0.
cu
o
(0
-=0p
r
0
-
2
Q
x
-o
-o
_
_
_E
1
L:
.N
--
_
I-0
-o
-0ofn
i.
0
c
123
Table 2.
1H
NMR spectra data for 5-12
Compounds (ppm)
5
Mult
J (Hz)
Assignment
-0.04
S
6
CSi(CH 3) 2
0.14
s
6
OSi(CH3)2
2.01
7.06-7.32
S
4
CH2
m
20
Ph
0.43
q
4
CH 2 SiCH 2 CH 3
0.57
q
4
OSiCH2CH3
0.68
t
7.8
7.6
7.8
6
CH2 SiCH 2 CH3
0.79
2.09
t
7.6
6
OSiCH2 CH3
$
4
CH 2
7.06-7.33
m
20
Ph
0.10
d
3
0.16
2.05
d
dd
3.6 ( 3 J)
1.5 ( J)
3
SiHCH3
OSiHCH3
14.2 ( 2 J)
2
CHaHbSiHCH3
2
CHaHbSiHCH3
1
CH2SiHCH3
3
4.0
10
Area
( 3 J)
14.2 ( 2 J)
2.18
d
4.05
m
4.65
d
7.09-7.34
m
20
Ph
2.62
s
4
CH 2
6.61-7.42
m
40
Ph
0.62
m
8
SiCH2 CH 3
0.84
t
12
SiCH 2CH 3
2.10
s
4
CH2
7.23-7.38
m
20
Ph
2.56
s
4
CH 2
6.71-7.38
m
40
Ph
1.5 ( 3 J)
7.8
1
OSiHCH
3
124
Table 2 continued
11
12
0.02
0.05
s
12
CH2Si(CH3 ) 2
s
12
OSi(CH 3) 2
1.99
s
4
CH 2
7.01-7.35
m
20
Ph
0.08
6
CH2Si(CH3) 2
0.16
0.19
1.82
s
s
6
Si(CH 3 ) 2
s
6
OSi(CH 3) 2
s
4
CH 2
7.03-7.29
m
20
Ph
125
Table 3.
13 C
NMR data for 5-12
Compound
8 (ppm)
Mult
J (Hz)
Assignment
5
-2.7
-2.3
24.7
q
118.8
CSi(CH 3) 2
q
19.7
OSi(CH 3 ) 2
t
121.1
CH 2
120.5
s
125.3-146.2
m
146.9
t
3.9
4.9
m
m
5.9
7.0
m
SiCH2 CH 3
SiCH2 CH 3
SiCH 2 CH3
m
SiCH 2CH3
21.3
t
120.4
125.2-142.3
m
147.4
t
-5.3
dq
6
7
CH2C=CPh2
Ph
5.8 (2 J)
120.5
dq
CH2C=CPh2
122.2
CH 2 SiHCH
8
t
m
22.8
t
122.5
S
125.7-141.2
m
145.4
t
OSiHCH
3
( 2 J)
114.5
CH2 SiHCH 3
CH2C=CPh2
Ph
S
124.6-141.9
146.4
3
( 2 J)
119.5
17.3
21.7
121.4
CH2SiCH2CH 3
CH2C=CPh2
Ph
5.9 (2 J)
18.7
-2.6
CH2C=CPh2
CH2C=CPh2
122.0
CH2 SiPh2
CH2C=CPh2
Ph
5.8 ( 2J)
CH2C=CPh2
126
Table 3 continued
9
10
11
12
5.8
SiCH2 CH3
SiCH 2CH3
CH2SiCH2CH3
CH2 C=CPh2
Ph
6.1
m
m
23.8
t
120.3
s
123.9-142.5
m
146.7
t
5.8 ( 2 J)
CH2C=CPh2
24.4
t
120.4
122.3
$
124.4-141.7
m
CH2 SiPh2
CH2C=CPh 2
Ph
144.8
t
5.8 ( 2 J)
CH2C=CPh 2
-3.2
q
119.8
Si(CH 3 ) 2
-3.1
q
119.9
Si(CH 3 ) 2
24.9
t
122.0
CH 2
121.5
s
125.2-142.8
m
149.0
t
6.0 (2 J)
CH2C=CPh2
-7.8
q
120.0
CH2Si(CH 3 ) 2
-3.1
q
117.0
Si(CH 3 ) 2
1.0
q
120.0
OSi(CH 3) 2
121.4
CH2
24.3
119.5
s
123.8-142.8
m
149.3
t
120.5
CH2 C=CPh 2
Ph
CH2C=CPh2
Ph
6.0 (2 J)
CH2C=CPh2
127
The 1H and
13C
NMR spectra do not give conclusive evidence concerning the
structures of 8 and 10. However, the 2 9 Si NMR spectra support the structures as shown.
The 29 Si NMR spectrum of 8 (Figure 9) shows two resonances for two chemically
inequivalent Si atoms, while the spectrum of 10 (Figure 10) shows one silicon signal for
two chemically equivalent silicon atoms. Therefore, based on the 29SiNMR spectral data,
structure A can be assigned to compound 8 while structure B can be assigned to
compound 10.
Comparatively, compounds 5-7 exhibit two resonances for chemically inequivalent
Si atoms in the 29 Si NMR spectra, indicating structure A for 5-7. Compound 9 has only
one resonance in the 29SiNMR spectrum, supporting the assignment of structure B for 9.
The 29 Si NMR spectral data for 5-12 are given in Table 4.
128
Table 4.
29 Si
NMR spectra data for 5-12
Assignment
Compound
8 (ppm)
5
-6.2
3.4
CH2Si(CH 3 )2
-7.64
7.25
CH 2 Si(CH2CH 3 )2
6
7
8
9
10
11
12
-21.2
-10.4
-36.6
-9.4
13.6
J (Hz)
OSi(CH 3 )2
OSi(CH2CH 3 ) 2
202.6
261.5
CH2SiHCH3
OSiHCH
3
CH2 SiPh2
OSiPh 2
Si(CH2CH3)2
-10.7
-14.7
CH2Si(CH3)2
10.0
OSi(CH 3 ) 2
-56.1
CH 2 Si(CH 3 ) 2
-17.9
19.4
SiSi(CH 3 ) 2 Si
SiPh 2
OSi(CH 3 )2
129
a
I.
4
.-
-to
o
i
I
-
o
(\1
i
e
rD, 9E-
_
,
"
_O
uO
130
I-
a
'-4
0
-mU,D
2
Lu
41
I"r
Iu
.
CT
z(a
09
OTZ'O-
zz
i-V
a%
N
-D
LI
L
c;
P"
131
The reactions of compounds 5 and 11 with MeLi were examined. Organometallic
reagents, such as RLi, have long been known to cleave Si-O bonds. 5 Treatment of
compound 5 with two equivalents of MeLi in ether at 0 °C gave the novel acyclic 5diketosilane 13 after aqueous workup. Compound 13 can be recrystallized from hexane
as colorless, air-stable crystals in 80% yield. Compound 13 is quite soluble in hexane,
chlorinated solvents, benzene, toluene, diethyl ether, and THF.
The structure of compound 13 was determined by spectroscopic analyses. The
NMR spectral data are given in Table 5. The 29 Si NMR spectrum of compound 13 shows
a single peak at 2.68 ppm, compared to two peaks for compound 5. The presence of the
carbonyl groups in this compound is confirmed by a peak at 206.2 ppm in the
13C
NMR
spectrum. The IR spectrum of 13 shows the characteristic carbonyl bond stretch frequency
at approximately 1693 cm -1 . The possible mechanism for the formation of this product
involves initial cleavage of two Si-O bonds by MeLi to form a dianion and followed by
quenching this dianion with saturated aqueous NH4C1solution as shown in Scheme 1.
132
Scheme
1
Me
Me
Ph
o Sio
Ph
C
Ph/
C=
H 2C
S
&Si\
O
I
Ph 2 C-C--
Me
0
I
II
Si--C-c
+
2 MeLi
\CP h
CH 2
Me
Me/
Li
/
OLi
i
Me
I
CPh2
I
C--- C-- Si-C-C=
Ph 2
HMe H 2
Me
H 2 I H2
Me
H+
Me
O
II
O
I
II
Ph2HC- C- C-- Si- C- C- CHPh2
H2
H2
Me
13
OLi
I
CPh2
133
Table 5. NMR spectral Data for 13
NMR
1H
13C
2 9 Si
(ppm)
Mult
J (Hz)
Area
Assignment
0.16
S
6
SiMe2
2.33
S
4
CH2
5.11
7.20-7.35
S
2
CHPh 2
m
20
Ph
1.9
q
120.3
SiMe 2
36.1
t
122.1
CH2
65.7
127.0-138.3
d
127.0
m
CHPh 2
Ph
206.2
s
C=O
2.68
s
SiMe2
134
Finally, the molecular structures of 8 and 10 were determined by single crystal Xray diffraction. Suitable single crystals of 8 were obtained by dissolving 8 in methylene
chloride and allowing the solution to evaporate slowly. Figure 11 shows an ORTEP plot
of the molecule. The eight-membered ring of 8 is crown-shaped. The Si-O and Si-C bond
distances (1.648(6); 1.633(6) and 1.910(8); 1.895(8) A) are normal and are in the ranges
(1.630-1.677 A and 1.872-1.894 A, respectively) observed in diverse cyclic silicon
compounds containing Si-0
6
and Si-C 7 (sp3 ) bonds in the ring. The C(1)-C(2) and C(5)-
C(6) bond distances, 1.340(11) and 1.358(12) A, respectively, are typical of C-C double
bonds.8 Single crystals of 10 were obtained by dissolving 10 in a minimum amount of
methylene chloride, adding two equivalents of hexane, and storing the solution at -23 0 C.
Figure 12 shows an ORTEP plot of 10. As in the case of the (1 5 -CsH5 )2Zr analog, the
eight-membered ring of 10 is crown-shaped. The Si-O (1.643(6) A) and Si-C (1.873(8)
and 1.862(7) A) bond distances are normal, and within the ranges for tetrahedral silicon. 6 ,7
The C(1)-C(5) and C(3)-C(6) bond distances, 1.321(13) A are in the range observed for
most normal C=C double bonds.8
135
r-
5
o0
SW
11.
2
o
6
u
a
E0
po
w
136
CN
uu
0
C)
w
A
5V
D
co
to
u
D4
e
9v
Cs
MN
· ro
rN
IL,
uu
u
1z
C3
i
C.
4
O
u
137
The structure of 11 is very difficult to determine on the basis of its 1 H, 13C, and
2 9 Si NMR
spectra. The 29 Si NMR spectrum shows two different signals. Both structures
A and B (Figure 13) have two chemically different silicon atoms and would show two
different signals in the 29 Si NMR spectrum. The structure of 12 was determined indirectly
by the reaction of 12 with 2 equivalents of MeLi, and confirmed by X-ray structure
analysis.
Me 2 Me 2
Me 2 Me 2
Si-Si
Ph\
c=c
Ph/ C--C
HzC
C2
CH
Ph
Ph
P
Ph
Ph
oSi- Si%
cH2
C=c
C%Ph
c=c
CC
HC
Si- Si
Si- Si
Me 2 Me 2
Me 2 Me 2
B
A
Figure 13. Two possible structures for ten-membered ring, 11
The reaction of compound 11 with two equivalents of MeLi was carried out
under similar conditions. After warming to room temperature, the reaction mixture was
quenched with aqueous NH4 C1. The anticipated 0-diketosilane 14 was not the observed
product, but rather the novel acyclic disilyl bisenol ether 15 was formed. The 1H, 13 C,
and 2 9Si NMR spectral data are given in Table 6. The 29Si NMR spectrum of 15 shows
a single signal at 10.65 ppm, compared to two peaks in the 2 9Si NMR spectrum of the
starting material 11. In the 1 H NMR spectrum of 15, the =CH2 protons appear as two
doublets due to the non-equivalent germinal protons coupling to each other with a coupling
constant of 2 J = 1.5 Hz. The
13 C
NMR spectral data for 15 are consistent with the results
from the 1H NMR spectrum. A possible mechanism for the formation of 15 could involve
initial formation of the 13-diketodisilane14, followed by isomerization via a Brook
rearrangement as shown in Scheme 2.
138
O-Ketosilanes are known to thermally convert to the isomeric siloxyalkenes in high
yield. Brook has suggested an intramolecular, concerted four-center mechanism which
involves attack by the carbonyl oxygen atom at silicon with simultaneous cleavage of the
silicon-carbon bond to form the olefin (Eq. 4).9 While the rearrangement of -ketosilanes
normally occurs upon prolonged heating (80-200' C for several hours), room temperature
rearrangement of 3-ketosilaneswas reported by Seyferth, Robison and Mercer.10
R3SiCH2-C-R'
[R3Si
, CR]
fi2
R3SiO-C-R'
(4)
CH2
The structure of 11 was confirmed by an X-ray structure analysis. Single X-ray
quality crystals were obtained by dissolving 11 in hexane and letting the solution stand at
room temperature for two days. An ORTEP plot of the observed structure is shown in
Figure 14. The Si(l)-Si(2) and S1(3)-Si(4) bond distances, 2.373(2) and 2.342(2) A,
respectively, are typical of Si-Si single bonds.1 1 The Si-O (1.676(3) and 1.664(3) A) and
Si-C (1.886(4) and 1.897(4) A) bond distances are normal, and within the ranges for
tetrahedral silicon.6, 7
139
Table 6. NMR spectral Data for 15
NMR
6
Mult
1H
0.06
s
3.93
4.14
4.63
7.14-7.25
13C
2 9 Si
-0.6
J (Hz)
2
Area
Assignment
12
SiMe2
d
1.5 ( J)
2
C=CHaHb
d
1.5 (2 J)
2
C=CHaHb
s
2
m
20
CHPh2
Ph
q
d
120.0
127.4
t
156.1
CHPh2
C=CH2
Ph
3.6 ( 2 J)
C=CH2
58.1
92.8
126.3-141.7
m
160.3
t
10.65
s
SiMe2
SiMe2
140
Scheme 2
Me2Me2
Si- Si
Ph
0
Ph
O0
I\
C
C/
C
Ph/
(
H 2 C,
Si-Si
+
_.
2 MeLi
Ph
,CH 2
Nk 2NVe2
e
OLi
I
Ph2C C-
I
e
OLi
I
O
I
C- Si-Si- C--C CPhH2
Me
II
u
- Ph--C-
I 1
H2
l~& lNt
O
I
I
H2 I
MleMe
If·
O
Me Ve
II
I
O
I
II
C- C- Si-i-i- C-CH
2
I I
Ntl Ntl
CHPh2
2
I
14
Nk
Ph2HC -C
.Si-
CHPh 2
H:
[
Ph 2 HC
Me e
I
CHPh 2
I
I
I
H2C= C- - Si-SiO- C=
CH2
I
I
Nkl Nkl
15
II
C- Si--Si-C-CH2
i
CPh2
141
It is interesting to note that the reaction of 5 with two equivalents of MeLi gives a
-diketosilane, while the reaction of 11 with two equivalents of MeLi gives disilyl bisenol
ether. The two different products from these reactions may be attributed to the different
intermediates (Scheme 3). Compound 13 has only one silicon atom, while compound
15 has two silicon atoms. The formation of 15 could involve two separate intramolecular,
concerted, four-membered ring intermediates with two silicon atoms available. If reaction
with compound 13 also involves this mechanism, the intermediate would involve two fourmembered rings joined at one silicon atom. This latter intermediate probably is less stable
than the former one.
142
I.'
0
1
a
co
PC
0
liw
F4
On
0
143
Scheme 3
O
e
II
I
Me
O
I
II
Ph2HC- C- C- Si- Si- C- C- CHPh
2
H2
H2
Ph2 HC-C
Si- Si
N*M
W
C- CHPh2
At H2
H2 M
14
I
O
O
11
1
Ph2HC- C- C- Si- C- C- CHPh2
H2
H2
C"
Me
H
I C C-CHPh2
P.2 kSI"
No -,I%
O
13
The 29 Si NMR spectrum for 12 shows three resonances which could result from a
six-membered ring or twelve-membered ring structure B (Figure 15). The twelvemembered ring structure A would give rise to four resonances in the
2 9 Si
NMR spectrum.
However, the mass spectrum for 12 shows the molecular ion peak corresponding to the
six-membered ring. Vapor pressure osmometry (VPO) molecular weight measurements
also agree with this result.
144
Me 2
Si
Me 2Si
SiMe 2
I
O,%
I
/,CH
2
PhC
Ph/\ P
Me 2
Me 2Si
Ph
'
Ph
Me2Si SiSiMe
SiSiMe2
0
/ Ph
C-C
Ph
Me 2
C- C\
'I
A
_
C= C
Ph
H2 C ,.CH
2
Me2Si ~ Six SiMe 2
Me 2
Ph\
Al
2
\
u
,z
/Ph
C:
PhC'
ph/
H2C
,OI
Si SiMe 2
x
Me2 Si .
rni
Me 2
B
Figure 15. Three possible structures for 12
In addition to the NMR spectra, compounds 5-12 were analyzed by IR
spectroscopy and electron impact, low resolution mass spectrometry. Selected data from
the IR spectra of these compounds are given in Table 7. Complete IR spectral data are
provided in the experimental section. The IR spectral data of 5-12 are quite similar to one
another, each exhibiting the characteristic stretches for Si-O groups (977-1077) and for
C=CPh 2 (1580-1636). In addition, the spectrum of 7 also shows two different
characteristic Si-H stretches at 2122 cm -1 and 2200 cm-1 (typical Si-H stretches are
between 2280 -2080 cm-1),1 2 supporting the presence of two inequivalent Si atoms in 6.
145
Table 7. Selected IR bands for 5-12
compound
Si-O (cm- 1 )
Si-H (cm- 1)
C = C (cm- 1 )
5
1077
1580
6
7
1004
1619
8
1077
1619
9
995
1622
10
11
12
1005
1629
971
1615
979
1614
1072
2122
2200
1636
Molecular ion peaks in the mass spectra of these compounds are given in Table 8.
The data show that the molecular ion peaks corresponding to dimers are observed in all
cases except 12. Compound 12 has a monomeric molecular ion, which supports the sixmembered, monomeric structure for 12. In the mass spectra of 9 and 10, besides the
molecular ion peaks, a [8] -- [4] decomposition of the eight-membered ring was observed.
This decomposition process was not observed in the mass spectra of 6 and 8 (the
positional isomers of 9 and 10, respectively). This further supports that 6 and 8 have
structure A, and 9 and 10 have structure B.
146
Table 8. Selected mass spectrometry data for 5-12
calcd. Mol. wt.
compounds
m/z (fragment, relative intensity)
5 (C34H3 6 Si2O2)
532
532 (M + , 53)
6 (C38H44Si2 02)
588
588 (M + , 31)
7 (C32H3 2Si2 02)
8 (C54H44Si202)
504
780
504 (M + , 34)
9 (C38H44Si202)
588
588 (M + , 35)
780 (M + , 18)
294 (0.5 M + , 18)
10 (C54H44Si202)
780
780 (M + , 25)
390 (0.5 M + , 9)
11 (C38H48Si2O2)
648
648 (M + , 42)
12 (C21H3OSi2O2)
382
382 (M + , 49)
The molecular weights of 5-12 in chloroform solution were determined by vapor
pressure osmometry. The VPO data for 5-12 are given in Table 9, They are in agreement
with the mass spectral data in showing molecular weights in solution corresponding to
"dimers" for 5-11 and a "monomer" for 12.
Table 9. VPO data for 5-12
compound
VPO: calculated/found
5 (C3 4H36 Si202)
532/545
6 (C3 8H44Si202 )
588/618
7 (C32 H32 Si20 2 )
504/534
8 (C 54H44Si2O 2 )
780/830
588/603
780/813
648/672
382/399
9 (C38H44Si202)
10 (C 5 4H44Si202)
11 (C3 8H48 Si202)
12 (C21H 30Si20 2 )
147
It is interesting to note that 5-11 have "dimeric" structures both in the solid state
and in solution. This is in contrast to what was found for the (S5 CsH)2Zr
5
analog
(Chapter 1). In the case of 5, 6, 7, 8, and 11, the structures of these compounds are all
different from that of the (S5 CHs 5)2Zr analog, 3. There are two chemically different
silicon atoms in these compounds. One silicon atom is bonded to two oxygen atoms which
basically makes dissociation into two four-membered monomeric ring compounds
impossible. Compounds 9 and 10 have structures similar to those of the (
5 C5H5)2Zr
analogs. However, they do not dissociate into two four-membered monomeric ring
compounds in solution. The coordination dimer 16 (Figure 16) probably is inaccessible,
due to the lesser Lewis acidity of Si in a R2SiOC environment comparing with Zr.
Ph
I
Ph-C
R2
H2
C-Si-O-C
I
I
I
I
C-O-
Si-C
H2
R2
C
Ph
Ph
16
Figure 16. A possible coordination dimer
Obtaining two regioisomers as products from the reaction of the same dianion,
[CH2C(O)CPh 2 ] 2 -, with R2SiCl 2 and R 2 SiF 2 was unexpected. In an effort to better
understand the reactivity of dianion 1 toward organosilicon dihalides, the regiochemistry of
silylations of 1,l-diphenylacetone monoanion and dianion has been investigated.
The monoanion of 1, 1-diphenylacetonecan be generated by the action of
potassium hydride or of the sterically hindered base, lithium diisopropylamide (LDA).
When the monoanion was generated with potassium hydride, 1,l-diphenylacetone was
148
deprotonated at the carbon bearing the phenyl groups (eq. 5). However, LDA
deprotonated 1,-diphenylacetone at the sterically less crowded methyl group (eq. 6).
Silylation of the two different monoanions resulted in different trimethylsilyl enol ethers,
17 and 18 in 79-86% yield. In both cases, exclusive O-silylation was observed.
Compound 17a,b are the thermodynamic products, and 18 is the kinetic product.
O
O
II
KH
Ph2CH-- C-- CH 3
IM
P
2
RSiCl
Ph2 C=C
OSiRM
2
(5)
CH,
17a R=Me
17b R =t-Bu
O
Ph 2CH-
II
C-
O
CH3 -
IDA
-
Ph 2CH-
II
C-
)
CH 2
3
SiCl
e3 SiO
C-- CH 2
Ph 2HC
18
Both compounds 17a and 18, have been mentioned in the literature. 13 , 14
However, compound 18 only has been observed as a side product in 5% yield. No
spectral data was reported for 18. The characterization of 17 and 18 includes 1H NMR,
13C NMR, and
2 9 Si
NMR spectral data, and elemental analyses. The NMR spectral data
for 18 are given in Table 10. In the 1H spectrum of 18, the --CH2 protons appear as two
doublets due to the non-equivalent geminal protons coupling to each other with a coupling
constant of 2 J = 2 Hz. Typical coupling constants for such non-equivalent geminal protons
are 0-7 Hz. The Ph2CH proton appears as a singlet at 4.69 ppm, and one SiMe3 resonance
is observed for this compound at 0.03 ppm. The
13 C
NMR spectrum also is consistent
with the assigned structure. The 29 Si NMR spectrum of 18 shows, as expected, only one
resonance at 17.31 ppm.
(6)
149
Table 10. NMR spectral Data for 18
NMR
8
Mult
J (Hz)
Area
Assignment
1H
0.03
s
-
9
SiMe3
4.02
d
2.1
( 2 J)
1
C=CHaHb
4.26
d
2.1 ( 2 J)
1
C=CHaHb
4.69
7.14-7.30
s
m
-
1
10
CHPh2
Ph
0.00
q
120.0
-
SiMe3
58.2
d
135.0
-
CHPh2
93.3
126.3-141.8
t
m
142.0
-
-
C=CH2
Ph
159.9
s
-
-
C=CH2
17.31
s
-
SiMe3
13 C
2 9 Si
When the 1,1-diphenylacetone dianion, 1, was reacted with two equivalents of a
monochlorosilane, bis-silylated products 19 and 20 were isolated in 71% and 82% yield,
respectively (eq. 7). The silylation reactions occurred at oxygen and the -CH 2 carbon
atom. No silylation product at the carbon bearing the phenyl groups was observed.
OSiRMe 2
2 Me 2RSiCl
Do-
Ph2C
C\
(7)
\CH 2SiRMe2
]
19 R=Me
1
20 R=H
Several mixed silylated products, 21-25, have been isolated from 1,1diphenylacetone dianion, 1, when one equivalent each of two different monochlorosilanes
was added successively (eq. 8). All reactions displayed regioselectively such that the first
150
chlorosilane reacted at the C-atom and the second chlorosilane reacted at the O-atom. The
only side product (less than 10%) was the bis-silylated product with the silyl group which
had been added first.
0
e
,.
'' (
IC
,'S
.
~;'
',(2)
C'CH2
Ph2
(1) Me2R'SiCl
MeR1R2SiCI
22OSiMeRiR
" Ph2C=C
(8)
CH 2 SiMe2 R'
21
R' = Me, 1R= Me, R2 = tBu
22 R'= Me, Ri =R 2 = Ph
23 R' = Me, R = Me, R2 =H
24 R' = H, 1 = Me, R 2 = tBu
25 R' = tBu, R1 = Me, R2 = H
In the isolation of 21-25, only small amounts of side products were observed
because the dianion reacts very rapidly with the first chlorosilane. The reaction of the 1,1-
diphenylacetone dianion, 1, with sterically hindered t-butyldimethylchlorosilane, 25,
proceeded very slowly and required stirring for 3 h before the second chlorosilane was
added.
Compounds 21, 22 and 23 can be purified by column chromatography.
Compounds 23 and 25 decomposed on the column due to the presence of the dimethylsilyl
group, and therefore preparative GC was used for the purification. Fractional distillation of
21-25 was unsuccessful due to the very close boiling points of these silyl enol ethers.
The characterization of 19-25 included 1 H NMR,
13 C NMR, 29 Si NMR
spectroscopy as well as elemental analysis. The 1 H NMR and
2 9 Si
and IR
NMR spectral data for
19-25 are given in Table 11 and Table 12, respectively. All the compounds exhibit
two silicon resonances in the 29Si NMR spectrum as expected from the O-silylation and C-
silylation.
151
Table 11. 1H NMR spectra data for 19-25
Compound8 (ppm)
19
-0.09
20
22
24
s
Area
Assignment
Si(CH 3 ) 3
-0.01
S
1.68
s
2
7.05
m
10
CH2Si
Ph
0.09
d
1.5 ( 3 J)
6
Si(CH 3 ) 2
0.16
d
1.5 ( 3 J)
6
OSi(CH 3 )2
1.88
d
1.5 ( 3 J)
2
CH2Si
3
1
CH2SiHCH3
3
1
OSiHCH 3
m
1.5 ( J)
OSi(CH 3) 3
4.57
7.26
m
10
Ph
-0.08
s
9
Si(CH 3 ) 3
0.08
0.86
s
6
OSi(CH 3 ) 2
9
SiC(CH 3) 3
1.88
s
s
2
7.23
m
10
CH2Si
Ph
-0.26
9
Si(CH 3 ) 3
3
OSiCH 3
1.43
s
s
s
2
CH2Si
7.05
m
20
Ph
0.03
s
9
Si(CH 3 ) 3
0.07
d
6
OSi(CH 3 ) 2
1.78
S
2
CH2Si
4.52
m
1
SiH
7.25
m
10
Ph
-0.38
d
6
HSi(CH3 )2
-0.17
s
6
OSi(CH 3) 2
0.56
1.59
S
9
SiC(CH 3 ) 3
2
CH2Si
0.16
23
J (Hz)
9
9
4.02
21
Mult
d
d
1.5 ( J)
2.5 ( 3 J)
2.5 (3 J)
2.4 (3 J)
2.4
(3 J)
152
Table 11 continued
25
3.72
m
6.88
-0.30
2 (3 J)
1
SiH
m
10
Ph
S
6
Si(CH 3 )2
6
OSi(CH 3 )2
(3 J)
-0.29
0.41
d
s
9
SiC(CH 3)3
1.43
S
2
CH2Si
4.16
6.92
m
1
SiH
10
Ph
2.5
2.5 (3 J)
m
Table 12. 2 9 Si NMR spectra data for 19-25
Compound
19
20
21
22
23
24
25
8 (ppm)
Assignment
2.43
CH2 SiMe 3
16.40
OSiMe3
-11.18
CH2SiMe2H
5.02
OSiMe2H
6.85
CH2SiMe 3
22.87
OSiMe2tBu
-4.22
CH2SiMe3
2.85
OSiMePh2
4.20
CH2SiMe 3
4.75
OSiMe2H
-11.78
CH2SiMe2H
21.18
OSiMe2tBu
-3.85
CH2SiMe2tBu
11.54
OSiMe2H
153
A proposed mechanism for the formation of mixed silylated products involves the
1,3 0->C silyl rearrangement of silyl enol ether anions (Scheme 4).
Scheme 4
O
ma
OSiR 3
R 3 SiCl
Ph 2C
I
CH2
OSiR 3
I
ON
a,,---
Ph2 C
CH2
Ph2C 'O CH 2
2
1
T-Csilyl migration
o
Ph 2C
OSiR3
R SiCl
CH 2 SiR 3
Ph 2 C
CH 2 SiR 3
To support the proposed mechanism, 17a was allowed to react with one
equivalent of LDA followed by quenching with one equivalent dimethylchlorosilane (eq.
9). Compound 23 was isolated in 37% yield by GC. No other silyl substituted products
were observed. Clearly, the Me 3 Si group has migrated from the O atom to the C atom.
OSiMe 3
(1)
I
(2) Me 2 HSiCl
Ph 2 C--C--
17a
CH3
LDA
OSiMe
'
Ph2C=C\
2H
(9)
---
---
CH2 SiMe 3
23
154
This result is contrary to the usual silyl migration which proceeds from carbon to
oxygen, as observed in the Peterson olefination and the Brook rearrangement. Corey and
Rucker has reported that when the TIPS (TIPS = triisopropylsilyl) enol ether of 4-tertbutylcyclohexanonewas treated with nBuLi/tBuOK base, two C-silylated ketone products
were isolated. A 1,3 O0-C silyl migration mechanism was proposed as shown in Scheme
5.15 Corey suggested that the 1,3 O0-C silyl migration was due to the higher stability of
an enolate anion in comparison with an allyl anion. Interestingly, when the trimethylsilyl
enol ether of 4-tert-butylcyclohexanonewas treated with the same base, only 4-tertbutylcyclohexanone was isolated. No C-silylation product was observed. Contrary to our
results, the TMS enol ether has been cleaved, instead of deprotonated, by the strong base.
Scheme 5
TIPS
_~~~
O
TIPS
nBuLi/tBuOK
H2 0~+
-
I
TIPS = triisopropylsilyl
I
+
155
A reaction in which only one molar equivalent of Me3SiCIwas added to a solution
of dianion 1, followed by quenching with dilute acid gave a mixture of three products:
Ph2CHC(O)CH2SiMe3(26) (40%, determined by integral ratios in the 1H NMR
spectrum), Ph2CHC(O)CH3 (40%), and Ph2C-C(OSiMe3)CH2SiMe3 (20%) (19), as
identified by the 1 H NMR spectrum (Eq. 10). GLC analysis also showed three products in
the ratio 40:40:20. GC/MS showed three molecular ion peaks at 282, 210 and 354. The
mixture could not be separated by long column distillation. Attempts at separating these
three products by column chromatography were unsuccessful. Passing the mixture
through a short column of either silica gel or alumina did not separate 26 from 19, but a
mixture of 26 and 19 containing a higher proportion of 19 was obtained. Passing this
mixture through a longer column resulted in the isolation of only 19 and diphenylacetone.
Apparently, 26 decomposes on the column. When the product mixture was passed
through a preparative GC column, a new compound Ph2CHC(OSiMe3)C=CH2, 18, was
isolated along with 19 and starting material diphenylacetone. No amount of 26 was
recovered.
0
11
Ph 2 CH -
C-
CH 2SiMe 3
(40%)
26
0
!.
.'
G
,
PhC'
/OSiMe
(1) Me 3 SiCl
3
(20%)
C
HPhfC
.CH2 2SiMe3
$iMe 3
@CH 2
19
210
Ph 2CH-
C-
CH 3
(40%)
(10)
156
A possible mechanism for the formation of 18 could involve the Brook
rearrangement of 26 (Scheme 6) similar to the formation of 15.
Scheme 6
Ph2CH-C-CH 2SiMe3
-
Ph2CH-=Cl. oSile3
2
C= CH2
Ph2CH
26
18
By careful comparison of the 1 H and 13 C NMR spectra of the mixture of
compounds with the data obtained from the spectra of 19 and starting material, the NMR
spectral data for 26 could be interpreted, and a structure assignment was possible for 26.
Figure 17 shows the 1 H NMR spectra of the mixture, 19 and 1,1-diphenylacetone. In
19, two separate SiMe3 resonances with the same intensity are observed, and in 26 only
one SiMe3 resonance is observed. The NMR spectral data extracted for 26 are given in
Table 13.
157
a
,f
IIIZ
I.... 4.I. . I
..
. . .
. . .
. . .
.
"a
E
w
*
w
1
I
iI
. .
-
4
4
I . .
. . . .
j
. . I ,
I
, I
a
, I I I
I I
I . . .
i
. . .
. . .
*
,
'AI:
4~'r~
m4
b
r · r··__
,. . a.
.-
-
-.-
I....j...
I....4
"
I....
''
.I..I
~~~~~-
II.-.I
1"
''
'
. .- . . 1.
.
-
I .
1
~~~~~~
. ~~TI$
r
'r
·
II
- - -1'llr
Or
IIr
C
I
,;o
Figure 17.
1H
i, 0
e0
.'
'
'.
I
'
NMR spectra of a) mixture, b) 19 and c) 1,1-diphenylacetone
158
Table 13. NMR spectral Data for 26
Assignment
NMR
6
Mult
J (Hz)
Area
1H
0.11
s
-
9
SiMe3
2.31
s
-
2
5.09
7.19-7.32
s
m
-
1
10
CH2
Ph2 CH
Ph
-1.18
q
118.9
-
SiMe3
37.9
t
123.0
-
CH2
65.1
124.9-149.2
d
m
127.0
-
-
Ph2CH
205.6
s
13C
Ph
C=O
While it is possible that 26 could be the hydrolysis product of 19, a separate
experiment showed 19 to be stable to hydrolysis under acidic conditions (Scheme 7).
Scheme
7
OSiMe
3
H30
I
Ph2 C = C-
CH 2SiMe
3
+
24
24 hrs
no reaction
19
From the above reactions, it is apparent that of the two reaction sites of the
[CH2C(O)CPh2] 2 - dianion, the -CH2- is favored, either via direct nucleophilic substitution
or via initial attack by the 0- site followed by 1,3 0-C
migration. In any case, the C-
silylation products are much more stable than the O-silylation products. This can help to
explain the different regioisomer products obtained in the reaction of dianion 1 with R2SiF2
and R2 SiC12. In the case of R2 SiF2 , 2-silaoxetane 28 can form initially as an intermediate,
which can undergo ring-opening cyclodimerization to give the observed 9 and 10. The
alkali metal fluoride released in the first step can aid in the formation of the 2-silaoxetane
159
(Scheme 8). The hypervalent organosilicon fluoride intermediate 27 has enhanced
reactivity 1 6 which favors ring closure to give 28. In the case of R2SiCl2, such reactivity
enhancement is not possible, so that intermediate 29 (Scheme 9) exists long enough to
undergo attack by another dianion 1. The resulting intermediate 30 then reacts with
another molecule of R2SiCl2 to give 5-8.
160
Scheme 8
2-
O
2
+
R 2 SiF 2
'
2M
+
F\/\
H2
CPh2
R 2Si
C
i
I
F
O-
27
1
CH2
2MF + [ R2 Si\ /C CPh
2
I]
28
R
Ph\
Si"CH 2
C
1/2
Ph/
R
C
C
H2 C\
R
9 R=Et
O
Si 0Ph
R
10 R=Ph
Ph
C
161
Scheme 9
2-
O
H2
.,
2M+ ''
+ RR2SiC1
2
I
I
-MC1 + M+
I~
Ph 2C
'CH
2
29
1
m
CPh2
11
/CH2 -C- OM+
RIR2 Si•
CH2 -C- OM+
II
CPh2
30
RiR 2 SiC12
R2
Rl
Si
Ph
1/2Ph/
C-C
c
Ph
SiCH
R1
Ph
2
R2
5 R 1 =R 2 =Me
6 R1 =R 2 =Et
7 R=Me,R
8 R=R
2 =H
2 =Ph
162
The possible mechanisms outlined above are speculative, but based on known
chemistry. 2-Silaoxetanes generally decompose readily to olefin and silanone, but
sterically hindered 2-silaoxetanes are stable (e.g., 2,2-bis(trimethylsilyl)-4,4-diphenyl-3is a crystalline solid). 1 7 Although ring-opening
adamantyl-3-trimethylsiloxy-2-silaoxetane
cyclodimerization has not been observed for a 2-silaoxetane, such processes are known for
2-silaoxacyclopentanes (eq. 11).18 In another example, Cragg has reported that the
reaction of diorganodichlorosilanes with 1,2-dihydroxybenzenein the presence of pyridine
afforded dioxasila heterocycles, which were dimeric at room temperature and monomeric at
higher temperatures. A transition state containing pentacoordinate silicon atoms has been
proposed (Scheme 10).19
e
C
/
SiCIMe2
I
-l
Si-O
Si
250 C
0
(CHi3
(CH2)3
(11)
0-Si
Me /
Cl
Scheme 10
m
I
R
.
R
I
RT
UR
1i- U
R
163
Attempts to react acetone dianion 2 with Me2SiC12 have not been successful. A
yellow oily mixture, which could be separated by distillation and column chromatography,
was obtained.
29 Si
NMR spectrum of this yellow mixture shows four major signals,
which could not be assigned
164
EXPERIMENTAL SECTION
General Comments.
All reactions were performed under an inert atmosphere using standard Schlenk
techniques. All solvents were distilled under nitrogen from the appropriate drying agents.
Chlorosilanes were purchased from Hills Inc. and distilled from magnesium chips before
use. n-Butyllithium in hexane was purchased from Aldrich and titrated for RLi content by
the Gilman double-titration method. 20 Methyllithium in ether was purchased from Johnson
and Matthey as a complex with lithium bromide. Potassium hydride was purified by
washing with THF solution of lithium aluminum hydride (approximately 4 mmol lithium
aluminum hydride in 10 mL THF).2 1 ,l-Diphenylacetone was purchased from Aldrich
and used without further purification. Tetramethyldichlorodisilane and
hexamethyldichlorotrisilanewere synthesized by methods reported in the literature.22 , 23
Gas chromatography (GLC) analyses were performed on a Hewlett-Packard 5890A
gas chromatography equipped with a 6 ft, 0.25 in column packed with 10% SE-30 silicon
rubber gum on Chromosorb P.
NMR spectra were obtained on either a Bruker AC-250 or Varian XL-300 NMR
spectrometer and listed in parts per million downfield from tetramethylsilane. 13CNMR
spectra, both proton coupled and decoupled, were obtained at 75.4 MHz in CDC13. 29 Si
NMR spectra were recorded at 59.59 MHz in CDC13 using tetramethylsilane as the external
standard at 0.00 ppm.
Electron impact mass spectra (MS) were obtained using a Finnigan-3200 mass
spectrometer operating at 70 eV. Infrared spectra (KBr) were obtained using a PerkinElmer 1600 Fourier Transform Infrared spectrophotometer. Melting points of analytically
pure crystalline and solid products were determined in air using a Biichi melting point
165
apparatus. Elemental analyses were performed by the Scandinavian Microanalytical
Laboratory, Herlev, Denmark.
166
Vapor Pressure Osmometry
Molecular weight determinations were carried out using a Wescan Model 233
Molecular Weight Apparatus (vapor pressure osmometry). Vapor pressure osmometry
operates on the principle that the vapor pressure of a solution is lower than that of the pure
solvent at the same temperature, but by raising the temperature of the solution its vapor
pressure can be raised to match that of the solvent. Equation 12 is derived from Raoult's
law and used for calculation of molecular weight.
AV= KxC
m
where
(12)
A V = a voltage change
C = concentration
m = molecular weight
K = calibration factor
Sucrose octaacetate was used as a standard and all measurements were carried out
in chloroform. The calibration factor K was determined by measuring A V and C for the
known molecular weight of sucrose octaacetate (Mol. Wt. 678.6). By reversing the
procedure, unknown molecular weights are determined using that factor K.
Three different concentration of sucrose octaacetate solution were prepared. The
results for determination of calibration factor K are given in Table 14. The Wescan
Model 233 Molecular Weight Apparatus were operated in the following condition:
Current: 50 microamperes.
Operating temperature: 400 C.
Average solvent reading: 2.0 microvolts.
167
Table 14. Determination of calibration factor K
Concentration
(mg/mL)
Reading
(microvolts)
(solution-solvent)
3.0
6.59
21.40
4.59
19.40
6.2
40.69
38.69
0.7
AV/C
AV
6.56
6.45
6.24
The determined values of AV/C are plotted versus concentration and a best fit
straight line is extrapolated to zero concentration. This extrapolated value of AV/C is used
to calculate the calibration factor K in equation 10 by multiplying it by the molecular weight
of the sucrose octaacetate. The extrapolates value is 6.62. The calibration factor K is
678.6 x 6.62 = 4492. The plot is show in Figure 18.
7.0
6.8
6.6
6.4
A V/C
4 6.2
6.0
5.8
5.6
0
1
2
3
4
5
6
C
Figure 18. Calibration factor K for VPO
7
168
X-ray Crystallography
Structure of 8
The structure of 8 was solved by Professor Arnold Rheingold at the University of
Delaware, Newark, DE.
Colorless crystals of 8 were obtained by dissolving 8 in methylene chloride and
allowing the solution to evaporate slowly. Data were collected at 238K using MoKa
radiation on a Siemens P4 diffractometer. The structure was solved by direct methods and
refined by full-matrix least-squares techniques. The non-hydrogen atoms were refined
anisotropically. An absorption correction was not applied. Final R = 0.0739 and Rw =
0.0807 for 2501 observed reflections (F > 4.Oa()
and 283 variables. The largest peak
on the final difference Fourier map was 0.51 eA -3. A summary of data collection details
and crystal data appear in Table 15-17
Table 15. Crystal data for 8.
Empirical formula
C 5 4 H4 40 2 Si 2
Color; Habit
Colorless block
Crystal Size (mm)
0.46 x 0.48 x 0.52
Crystal System
Space group
orthorhombic
Pbca
Unit Cell Dimensions
a= 11.676(4) A
b= 23.057(11) A
£= 31.850(15) A
Volume
8575(7) A3
z
8
Formula weight
781.1
Density(calc.)
1.210 g/cm 3
Absorption Coefficient
F(000)
0.124 mm' 1
3296
169
Table 16. Data collection for 8
DiffractometerUsed
Siemens P4
Radiation
MoKa (A = 0.71073
Temperature (K)
238
Monochromator
20 Range
Highly oriented graphite crystal
A)
4.0 to 42.00
Scan Type
Scan Speed
Variable; 6.51 to 19.530°/min. in co
Scan Range (co)
1.000
Background Measurement
Stationary crystal and stationary counter
at beginning and end of scan, each for
1.0% of total scan time
Standard Reflections
3 measured every 197 reflections
Index Ranges
0<h< 11,0<k23
0<1<32
Reflections collected
4593
Independent Reflections
4593 (Rint = 0.00%)
Observed Reflections
2501 (F > 4.0o(F))
Absorption Correction
N/A
170
Table 17 Structure solution and refinement for 8
System Used
Siemens SHELXTL PLUS (PC
Version)
Solution
Direct Methods
Refinement Method
Full-Matrix Least-Squares
Quantity Minimized
lw(Fo-Fc)2
Absolute Structure
N/A
Extinction Correction
N/A
Hydrogen Atoms
Riding model, fixed isotropic U
Weighting Scheme
w-1 = a 2 (F) + 0.0010F2
Number of parameters Refined
283
Final R Indices (obs. data)
R Indices (all data)
R = 7.39 %, wR 8.07 %
R = 13.81 %, wR 9.49 %
Goodness-of-Fit
1.46
Largest and Mean D/s
0.010, 0.001
Data-to-parameter Ratio
8.8:1
Largest Difference Peak
0.51 eA- 3
Largest Difference Hole
-0.39 eA-
3
171
Table 18
Atomic coordinates (x104) and equivalent isotropic displacement
coefficients (A2x 103) for 8
Atom
x
y
z
U(eq)
Si(l)
Si(2)
-909(2)
1583(2)
2449(1)
1333(1)
1318(1)
1260(10
31.9(8)*
31.5(8)*
0(1)
422(4)
2595(2)
1454(2)
32(2)*
0(2)
C(1)
-1064(4)
2091(7)
1786(2)
3059(3)
1146(2)
1206(2)
31(2)*
30(2)*
C(2)
C(3)
1548(7)
1548(7)
2050(3)
2050(3)
960(2)
960(2)
30(3)*
30(3)*
C(4)
C(5)
C(6)
C(11)
227(7)
-841(7)
-1527(7)
-1271(9)
1222(4)
1250(4)
796(3)
2913(4)
1577(2)
1322(2)
1219(2)
2119(3)
35(3)*
30(3)*
32(3)*
64(3)
C(12)
-1912(10)
3035(4)
2483(4)
77(3)
C(13)
C(14)
C(15)
C(16)
C(21)
C(22)
-2991(9)
-3463(9)
-2840(7)
-- 1731(7)
-2731(8)
-3664(8)
2802(4)
2489(4)
2366(4)
2585(3)
1240(4)
1207(4)
2519(3)
2212(3)
1854(3)
1801(2)
637(3)
364(3)
67(3)
58(3)
49(3)
32(2)
49(3)
53(3)
C(23)
C(24)
-4396(8)
-4210(9)
744(4)
323(4)
391(3)
675(3)
60(3)
63(3)
C(25)
C(26)
C(31)
C(32)
C(33)
C(34)
C(35)
C(36)
C(41)
C(42)
C(43)
C(44)
C(45)
C(46)
C(51)
C(52)
C(53)
C(54)
C(55)
C(56)
C(61)
-3286(8)
-2529(7)
-1641(9)
-1489(9)
-968(9)
-587(8)
-720(7)
-1263(7)
988(7)
2432(8)
2535(8)
1847(7)
1069(7)
1656(7)
2739(8)
3685(8)
4743(9)
4893(9)
3947(7)
2847(7)
3335(8)
345(4)
809(4)
64(4)
-499(4)
913(5)
759(4)
-206(3)
211(3)
824(4)
302(3)
-82(4)
-18(4)
431(3)
770(3)
1335(4)
1294(4)
1201(4)
1161(4)
1207(3)
1284(3)
3361(4)
947(3)
930(2)
1805(3)
1961(3)
1723(3)
1330(3)
1171(3)
1411(2)
481(2)
851(3)
519(3)
174(3)
153(3)
839(2)
2052(3)
2314(3)
2147(3)
1720(3)
1460(3)
1612(2)
614(3)
52(3)
34(2)
58(3)
64(3)
62(3)
56(3)
38(3)
32(2)
36(2)
38(2)
52(3)
46(2)
38(2)
29(2)
47(3)
62(3)
61(3)
56(3)
40(2)
32(2)
48(3)
C(62)
C(63)
4358(9)
5217(9)
3338(4)
3000(4)
389(3)
517(3)
68(3)
68(3)
C(64)
5138(9)
2677(4)
871(3)
66(3)
C(65)
4117(8)
2694(4)
1106(3)
47(3)
C(66)
3206(8)
3026(3)
975(3)
36(2)
172
C(71)
C(72)
C(73)
C(74)
C(75)
C(76)
C(81)
C(82)
C(83)
C(84)
C(85)
C(86)
797(9)
3862(4)
605(9)
1491(9)
2558(9)
4378(4)
2768(8)
1872(7)
-1095(8)
-1337(7)
-1848(7)
-2113(8)
-1873(7)
-1337(7)
4651(4)
4421(4)
3905(4)
3605(4)
2724(4)
3074(4)
3605(4)
3785(4)
3438(3)
2897(3)
1442(3)
1661(3)
1860(3)
1844(3)
1627(2)
1432(2)
454(3)
110(3)
176(3)
576(3)
912(3)
862(2)
53(3)
64(3)
54(3)
52(3)
41(2)
35(2)
47(3)
48(3)
47(3)
47(3)
38(2)
32(2)
173
Table 19
Intramolecular bond distances (A) for 8, involving the non-hydrogen
atoms.
Atom
Si(l)
Si(l)
Si(2)
Si(2)
0(1)
C(1)
C(1)
C(4)
C(6)
C(11)
C(12)
C(14)
C(21)
C(22)
C(24)
C(31)
C(32)
C(34)
C(41)
C(42)
C(43)
C(51)
C(52)
C(54)
C(61)
C(62)
C(64)
C(71)
C(72)
C(74)
C(81)
C(82)
C(84)
Atom
Distance
Atom
Atom
Distance
0(1)
1.648(6)
1.839(8)
1.910(8)
1.870(8)
1.390(10)
1.340(11)
1.471(11)
1.490(12)
1.490(11)
1.408(15)
1.375(16)
1.383(13)
1.396(13)
1.371(13)
1.385(14)
1.401(14)
1.361(14)
1.382(12)
SI(1)
0(2)
1.633(6)
Si 1)
C(86)
C(4)
C(56)
C(5)
C(66)
C(3)
C(6)
C(36)
C(16)
C(14)
C(16)
C(26)
C(24)
C(26)
C(36)
C(34)
C(36)
C(46)
C(46)
C(45)
C(56)
C(54)
C(56)
C(66)
C(64)
C(66)
C(76)
C(74)
C(76)
C(86)
C(84)
C(86)
1.850(8)
1.895(8)
1.856(8)
C(16)
C(3)
C(46)
C(2)
C(2)
C(76)
C(5)
C(26)
C(12)
C(13)
C(15)
C(22)
C(23)
C(25)
C(32)
C(33)
C(35)
C(45)
C(43)
C(44)
C(52)
C(53)
C(55)
C(62)
C(63)
C(65)
C(72)
C(73)
C(75)
C(82)
C(83)
C(85)
1.387(11)
1.385(12)
1.368(12)
1.387(13)
1.361(14)
1.385(13)
1.394(14)
Si(2)
Si(2)
0(1)
C(1)
C(2)
C(5)
C(6)
C(11)
C(13)
C(15)
C(21)
C(23)
C(25)
C(31)
C(33)
C(35)
C(41)
C(42)
C(44)
C(51)
C(53)
C(55)
C(61)
1.335(15)
C(63)
1.408(14)
1.396(13)
1.367(14)
1.397(12)
1.390(12)
1.378(12)
1.365(12)
C(65)
C(71)
C(73)
C(75)
C(81)
C(83)
C(85)
1.382(10)
1.498(12)
1.492(11)
1.358(12)
1.512(11)
1.375(12)
1.333(14)
1.400(12)
1.384(12)
1.343(14)
1.389(13)
1.375(12)
1.374(13)
1.382(11)
1.386(11)
1.408(12)
1.380(12)
1.411(11)
1.372(13)
1.386(12)
1.391(12)
1.354(14)
1.377(12)
1.389(13)
1.355(14)
1.399(12)
1.391(11)
1.377(12)
1.404(11)
174
Table 20 Intramolecular bond angles () for 8, involving the non-hydrogen atoms.
Atom
Atom
Atom
Angle
0(1)
0(2)
0(2)
Si(l)
Si(l)
Si(l)
0(2)
C(3)
C(4)
C(4)
Si(1)
C(2)
C(66)
Si(2)
Si(2)
Si(2)
0(1)
C(2)
C(3)
112.6
112.4
103.3
111.4
109.1
109.5
129.3
118.7
115.8
113.1
117.5
114.6
126.3
118.0
121.5
117.4
119.4
122.8
122.2
123.4
120.6
121.8
Si(2)
0(2)
C(4)
C(5)
Si(l)
C(6)
C(6)
Si(2)
Si(2)
C(1)
C(1)
Si(1)
0(1)
C(1)
C(1)
C(5)
C(5)
C(6)
C(16)
C(26)
C(36)
C(46)
C(56)
C(66)
C(76)
C(86)
C(16)
C(86)
C(4)
C(46)
C(56)
C(2)
C(66)
C(76)
C(3)
C(2)
C(4)
C(6)
C(36)
C(15)
(25)
C(35)
C(42)
C(55)
C(65)
C(75)
C(85)
Atom
Atom
Atom
Angle
(3)
(3)
(3)
(4)
0(1)
0(1)
Si(l)
Si(l)
Si(l)
(4)
(4)
(5)
C(3)
C(46)
Si(l)
0(2)
C(16)
C(86)
C(86)
C(46)
C(56)
C(56)
C(5)
(7)
(7)
(7)
(5)
(7)
C(2)
(8)
C(5)
C(26)
C(1)
C(2)
C(2)
C(4)
C(5)
C(6)
C(6)
C(16)
C(26)
C(36)
C(46)
103.7
110.3
114.8
104.0
111.8
110.8
132.9
125.4
119.7
127.2
113.8
118.7
126.7
115.4
120.5
124.4
121.6
120.1
121.6
118.2
122.2
121.2
(7)
(6)
(7)
(7)
(6)
(6)
(7)
C(16)
C(3)
0(1)
C(1)
Si(2)
0(2)
Si(l)
C(6)
(8)
C(6)
Si(2)
Si(2)
C(1)
C(1)
(6)
Si(l)
Si(2)
Si(2)
Si(2)
C(56)
C(66)
C(76)
C(86)
C(76)
C(1)
C(3)
C(5)
C(6)
C(26)
C(36)
C(11)
C(21)
C(31)
C(41)
C(51)
C(61)
C(71)
C(81)
(3)
(3)
(4)
(3)
(4)
(4)
(5)
(7)
(7)
(7)
(5)
(7)
(7)
(7)
(7)
(8)
(7)
(6)
(6)
(8)
(8)
(6)
175
Structure of 10
The structure of 10 was solved by Professor Arnold Rheingold at the University of
Delaware, Newark, DE.
Colorless crystals of 10 were obtained by dissolving 10 in a minimum amount of
methylene chloride, adding two equivalents of hexane, and storing the solution at -23°C.
Data were collected at 296 K using MoKa radiation on a Siemens P4 diffractometer. The
structure was solved by direct methods and refined by full-matrix least-squares techniques.
The limited available data required the use of rigid-body constraints on the phenyl rings and
prevented anisotropic refinement of their carbon atoms. The non-hydrogen atoms were
refined anisotropically. An absorption correction was not applied. Final R = 0.0549 and
Rw = 0.0642 for 2022 observed reflections (F > 5.0(F)) and 427 variables. The largest
peak on the final difference Fourier map was 0.22 eA-3. A summary of data collection
details and crystal data appear in Table 21-23
176
Table 21. Crystal data for 10.
Empirical formula
Color; Habit
C 5 4 H440 2 Si 2
Colorless block
Crystal Size (mm)
0.16 x 0.42 x 0.80
Crystal System
Monoclinic
Space group
P21/n
Unit Cell Dimensions
a.= 10.384 (2)
A
bh= 19.762 (4) A
£c= 21.513 (5) A
1 = 96.65 (2)0
Volume
z
4384.9 (16) A 3
4
Formula weight
781.1
Density(calc.)
1.183 g/cm 3
Absorption Coefficient
0.122 mm '1
F(000)
1648
177
Table 22. Data collection for 10
Diffractometer Used
Radiation
Siemens P4
MoKa (1= 0.71073 A)
Monochromator
296
Highly oriented graphite crystal
20 Range
4.0 to 42.0 °
Scan Type
0-20
Scan Speed
Variable; 7.00 to 20.00°/min. in 0
Scan Range (o)
1.000
Background Measurement
Stationary crystal and stationary counter
Temperature (K)
at beginning and end of scan, each for
50.0% of total scan time
Standard Reflections
3 measured every 100 reflections
Index Ranges
-9<h< 10,-19<k<0
-9< 1
21
Reflections collected
4889
Independent Reflections
4740 (Rint = 1.61%)
Observed Reflections
2022 (F > 5.0a(F))
Absorption Correction
N/A
178
Table 23 Structure solution and refinement for 10
System Used
Siemens SHELXTL PLUS (PC
Version)
Solution
Direct Methods
Refinement Method
Full-Matrix Least-Squares
Quantity Minimized
w(Fo-Fc) 2
Absolute Structure
N/A
Extinction Correction
N/A
Hydrogen Atoms
Riding model, fixed isotropic U
Weighting Scheme
w- = a 2 (F) + 0.0010F2
Number of parameters Refined
427
Final R Indices (obs. data)
R Indices (all data)
R = 5.49%, wR6.42 %
R = 12.21 %, wR 7.83 %
Goodness-of-Fit
1.29
Largest and Mean D/s
0.011, 0.001
Data-to-parameter Ratio
4.7:1
Largest Difference Peak
0.22 eA -3
Largest Difference Hole
-0.25 eA- 3
179
Table 24
Atomic coordinates (x10 4) and equivalent isotropic displacement
coefficients (A2x103) for 10
Atom
x
y
z
U(eq)*
Si(1)
Si(2)
0(1)
0(2)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
C(31)
C(32)
C(33)
C(34)
1756(2)
2664(2)
2237(5)
1135(5)
3362(8)
3790(7)
448(9)
1249(7)
3886(9)
-810(9)
3291(8)
4288
5086
4885
3888
3091
-456(8)
-1507
-1778
-997
54
325
4127(6)
3627
2335
1544
1954(1)
2485(1)
2728(3)
2401(3)
2942(5)
2502(4)
1901(5)
1483(4)
3519(5)
1855(5)
801(5)
468
826
1517
1849
1491
1536(3)
1633
2277
2824
2727
2083
4108(4)
4493
4702
4527
2584(1)
971(10
2453(2)
1084(2)
2222(4)
1710(3)
1353(4)
1840(3)
2433(4)
1177(4)
2965(3)
3335
3787
3870
3500
3048
3140(3)
3479
3696
3573
3234
3017
3462(4)
3923
3838
3293
53(1)
52(1)
55(2)
57(2)
50(4)
49(3)
49(4)
54(3)
56(3)
59(4)
90(5)
114(6)
119(8)
105(6)
83(5)
59(4)
86(5)
114(7)
111(6)
109(6)
80(5)
53(4)
129(7)
178(9)
131(8)
126(7)
C(35)
2044
4142
2833
113(6)
C(36)
C(41)
C(42)
C(43)
C(44)
C(45)
C(46)
C(51)
C(52)
C(53)
C(54)
3336
6283(10)
7400
7327
6137
5020
5093
1854(6)
2018
3080
3978
3933
3466(3)
3713
4277
4594
4347
3783
3835(5)
4475
4605
4094
2918
2375(3)
2151
1758
1591
1815
2208
666(3)
413
89
18
70(5)
86(5)
107(6)
123(8)
117(6)
82(5)
62(4)
107(6)
128(7)
100(6)
106(6)
C(55)
3814
3454
270
83(5)
C(56)
C(61)
C(62)
C(63)
C(64)
C(65)
C(66)
C(71)
2752
4389(7)
4685
3699
2418
2122
3108
-1460(7)
3324
1558(4)
1024
704
918
1452
1772
3009(6)
594
471(3)
88
-300
-305
79
467
757(4)
58(4)
71(5)
83(5)
80(5)
80(5)
68(4)
50(4)
139(7)
180
C(72)
-2128
3414
296
185(9)
C(73)
C(74)
-2829
-2863
3117
2414
-226
-286
169(11)
193(12)
C(75)
C(76)
-2195
-1494
2009
2306
174
696
134(6)
77(5)
C(81)
C(82)
-1447(6)
-2236
670(5)
225
1446(3)
1735
94(6)
109(6)
C(83)
-3240
477
2047
117(7)
C(84)
-3455
1173
2070
116(7)
C(85)
-2666
1617
1781
98(5)
C(86)
-1662
1366
1469
67(5)
*The limited available data required the use of rigid-body constraints on the phenyl rings
and prevented anisotropic refinement of their carbon atoms.
181
Table 25 Intramolecular bond distances (A) for 10, involving the non-hydrogen atoms.
Atom
Atom
Distance
Atom
Atom
Distance
Si(l)
0(1)
Si(l)
C(16)
Si(2)
Si(2)
0(2)
0(1)
C(1)
C(1)
C(3)
C(5)
C(6)
1.643
1.853
1.641
1.853
1.388
1.510
1.507
1.490
1.484
C(56)
C(2)
C(4)
C(36)
C(76)
(6)
SI(1)
(8)
Si(l)
(6)
(9)
(10)
(12)
(11)
(13)
Si(2)
Si(2)
0(2)
C(1)
C(3)
C(5)
C(6)
(13)
C(4)
C(26)
C(2)
C(66)
C(3)
C(5)
C(6)
C(46)
C(86)
1.873
1.861
1.862
1.869
1.384
1.321
1.321
1.490
1.496
(8)
(9)
(7)
(8)
(11)
(13)
(13)
(14)
(13)
Table 26 Intramolecular bond angles () for 10, involving the non-hydrogen atoms.
Atom
Atom
Atom
Angle
0(1)
Si(l)
Si(l)
Si(l)
Si(2)
C(4)
C(16)
C(26)
C(56)
C(56)
C(66)
0(1)
C(1)
112.2
109.5
109.5
113.4
107.4
109.6
129.0
114.7
127.1
114.4
127.5
C(4)
C(4)
0(2)
Si(2)
C(2)
C(2)
Si(1)
Si(2)
0(1)
C(1)
C(1)
C(3)
C(3)
C(2)
0(2)
C(4)
C(1)
C(36)
C(3)
Si(1)
Si(l)
C(5)
C(5)
Si(2)
Si(2)
C(6)
C(6)
C(5)
C(5)
C(6)
C(16)
C(26)
C(36)
C(46)
C(56)
C(66)
C(76)
C(86)
C(2)
C(5)
(4)
C(6)
C(36)
C(46)
C(86)
C(11)
C(21)
C(31)
C(41)
C(51)
C(61)
C(71)
C(81)
(3)
(4)
(3)
(3)
(3)
(3)
(5)
(7)
(8)
(7)
(8)
122.6 (8)
116.1
122.5
121.8
120.3
119.2
120.8
122.1
121.6
121.9
121.1
(7)
(8)
(3)
(2)
(4)
(4)
(2)
(2)
(6)
(5)
Atom
Atom
Atom
Angle
0(1)
Si(l)
109.1 (4)
C(1)
C(16)
C(26)
C(26)
C(56)
C(66)
C(66)
C(3)
C(5)
Si(2)
C(2)
0(2)
Si(l)
C(1)
C(3)
C(6)
C(3)
C(46)
118.1 (8)
C(76)
122.4 (9)
C(86)
C(15)
C(25)
C(35)
C(45)
C(55)
C(65)
C(75)
C(85)
115.0
118.2
119.7
120.8
119.2
117.7
118.4
118.1
118.8
0(1)
Si(l)
C(16)
Si(l)
0(2)
0(2)
Si(2)
Si(2)
Si(2)
C(56)
Si(2)
0(1)
C(1)
C(3)
C(76)
Si(l)
Si(l)
C(5)
C(5)
Si(2)
Si(2)
C(6)
C(6)
0(2)
C(4)
C(5)
C(6)
C(6)
C(16)
C(26)
C(36)
C(46)
C(56)
C(66)
C(76)
C(86)
103.5
112.9
104.7
108.5
113.2
133.5
118.0
115.1
(3)
(3)
(3)
(3)
(3)
(5)
(8)
(5)
113.5 (6)
121.3 (8)
(7)
(3)
(2)
(4)
(4)
(2)
(2)
(6)
(5)
182
Structure of 11
The structure of 11 was solved by Professor Arnold Rheingold at the University of
Delaware, Newark, DE.
Colorless crystals of 11 were obtained by dissolving 11 in hexane and letting
solution stand at room temperature for two days. Data were collected at 233 K using
MoKaoradiation on a Siemens P4 diffractometer. The structure was solved by direct
methods and refined by full-matrix least-squares techniques. The non-hydrogen atoms
were refined anisotropically. An absorption correction was not applied. Final R = 0.0496
and Rw = 0.0629 for 4102 observed reflections (F > 5.0a(F)) and 425 variables. The
largest peak on the final difference Fourier map was 0.28 eA- 3. A summary of data
collection details and crystal data appear in Table 27-29.
Table 27. Crystal data for 11.
Empirical formula
C 4 1H 505
Color; Habit
Colorless block
Crystal Size (mm)
0.24 x 0.36 x 0.40
Crystal System
Space group
Monoclinic
Unit Cell Dimensions
a= 29.901 (6)
2 Si4
P2 1/n
A
bL= 9.926 (1) A
Qc= 14.221 (4) A
p = 97.78 (2)0
Volume
4181.9 (14) A 3
z
4
Formula weight
692.2
Density(calc.)
1.099 g/cm 3
Absorption Coefficient
0.173 mm '1
F(000)
1492
183
Table 28. Data collection for 11
Diffractometer Used
Siemens P4
Radiation
MoKa (1 =0.71073
Temperature (K)
233
Monochromator
Highly oriented graphite crystal
20 Range
7.0 to 42.00
Scan Type
Ct)
Scan Speed
Variable; 2.00 to 29.300°/min. in o
Scan Range (co)
0.060
Background Measurement
Stationary crystal and stationary counter
A)
at beginning and end of scan, each for
0.5% of total scan time
Standard Reflections
3 measured every 100 reflections
Index Ranges
-34< h33,0<k<
0<1<16
Reflections collected
Independent Reflections
6879
6567 (Rint = 3.70%)
Observed Reflections
4102 (F > 5.0a(F))
Absorption Correction
N/A
11
184
Table 29 Structure solution and refinement for 11
System Used
Siemens SHELXTL PLUS (PC
Version)
Solution
Refinement Method
Direct Methods
Quantity Minimized
w(Fo-Fc)
Absolute Structure
N/A
Extinction Correction
X = 0.00016 (8), where
Full-Matrix Least-Squares
2
F* = F [1+ 0.0002XF 2 /sin(20)]Weighting Scheme
Riding model, fixed isotropic U
w'l = o2(F) + 0.0010F2
Number of parameters Refined
425
Final R Indices (obs. data)
Largest and Mean A/la
R = 4.96 %, wR 6.29 %
R = 8.72 %, wR 7.48 %
1.26
0.138, 0.014
Data-to-parameter Ratio
9.7:1
Largest Difference Peak
0.28 eA- 3
Largest Difference Hole
-0.24 eA -3
Hydrogen Atoms
R Indices (all data)
Goodness-of-Fit
1/4
185
Table 30
Atomic coordinates (x104 ) and equivalent isotropic displacement
coefficients (A2x103) for 11
Atom
x
Si(1)
Si(2)
y
z
2709.4(4)
6427(1)
616.7(8)
1942.6(4)
33.9(4)
6747(1)
Si(3)
Si(4)
0(1)
0(2)
-30.1(8)
2264.7(4)
2556.9(4)
2940.8(8)
1791(1)
2642(1)
4253(1)
5208(3)
5538(3)
37.5(4)
C(1)
C(2)
C(3)
C(4)
-1278.2(8)
-2233.2(8)
26(2)
-820(2)
2759(2)
3048(1)
1566(2)
1854(2)
33.2(4)
33.8(4)
33(9)
37(1)
5790(5)
7984(4)
6695(5)
8322(4)
C(5)
1859(3)
550(3)
907(3)
-728(3)
1608(1)
50(2)
46(2)
61(2)
58(2)
4309(4)
C(6)
C(7)
C(8)
C(9)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(21)
C(22)
C(23)
C(24)
-602(3)
1160(1)
1962(1)
1838(1)
2726(1)
2094(1)
2977(1)
2849(1)
3162(1)
3615(1)
4016(2)
4501(2)
4765(2)
901(2)
601(2)
238(2)
172(2)
35(1)
4130(4)
3285(4)
1681(4)
1500(4)
4918(5)
3343(4)
5780(4)
5483(4)
5394(4)
3944(7)
3751(6)
5058(6)
5936(5)
6933(6)
7215(6)
6518(7)
C(25)
C(26)
-736(3)
-289(3)
-2103(3)
-724(3)
-3133(3)
-2867(3)
-1627(3)
-744(3)
-673(3)
4279(4)
4626(4)
4763(4)
-1930(3)
-2275(4)
-1845(5)
-1055(6)
467(2)
841(1)
44(2)
36(1)
52(2)
51(2)
56(2)
49(2)
34(1)
30(1)
30(1)
100(3)
87(3)
82(2)
61(2)
79(2)
95(3)
126(4)
5511(6)
5204(4)
-703(5)
-1141(4)
C(31)
C(32)
C(33)
99(3)
51(2)
1011(2)
834(2)
608(2)
2442(6)
1223(7)
393(8)
C(34)
C(35)
C(36)
C(41)
C(42)
C(43)
C(44)
C(45)
C(46)
500(4)
754(6)
76(8)
550(2)
725(2)
964(1)
3857(1)
4076(2)
4278(1)
4273(1)
4060(1)
3844(1)
68(2)
99(3)
129(5)
812(7)
2010(6)
2841(5)
7173(4)
7579(5)
6653(5)
5328(5)
4906(4)
5822(4)
-841(7)
-1104(5)
-440(4)
-1755(3)
-2500(3)
-3011(3)
-2774(3)
-2011(3)
-1497(3)
C(51)
C(52)
C(53)
C(54)
C(55)
122(4)
84(2)
52(2)
43(2)
54(2)
52(2)
51(2)
40(1)
33(1)
4362(1)
4658(1)
4520(2)
4084(2)
3784(1)
5394(4)
4942(5)
4019(5)
3557(5)
4011(4)
C(56)
339(3)
1107(3)
1732(3)
1580(3)
824(3)
3916(1)
42(1)
52(2)
55(2)
52(2)
42(1)
4939(4)
184(3)
32(1)
U(eq)
186
Table 31 Intramolecular bond distances (A) for 11, involving the non-hydrogen atoms.
Atom
Atom
Distance
Atom
Atom
Distance
Si(1l)
Si(1l)
Si(2)
Si(2)
0(1)
C(16)
C(3)
C(46)
0(1)
C(2)
C(1)
C(1)
C(2)
C(76)
1.648
1.839
1.910
1.870
(6)
(8)
(8)
(8)
SI(1)
Si(1l)
Si(2)
Si(2)
0(2)
C(86)
C(4)
C(56)
1.633
1.850
1.895
1.856
(6)
(8)
(8)
(8)
1.390 (10)
0(1)
C(5)
1.382 (10)
1.340 (11)
1.471 (11)
C(1)
C(2)
C(66)
C(3)
1.498 (12)
1.492 (11)
C(4)
C(5)
1.490 (12)
C(5)
C(6)
1.358 (12)
C(6)
C(11)
C(26)
C(12)
1.490 (11)
1.408 (15)
C(6)
C(11)
C(36)
C(16)
1.512 (11)
1.375 (12)
C(12)
C(14)
C(13)
C(15)
1.375 (16)
1.383 (13)
C(13)
C(15)
C(14)
C(16)
1.333 (14)
1.400 (12)
C(21)
C(22)
1.396 (13)
C(21)
C(26)
1.384 (12)
C(22)
C(24)
C(31)
C(23)
C(25)
C(32)
1.371 (13)
1.385 (14)
1.401 (14)
C(23)
C(25)
C(31)
C(24)
C(26)
C(36)
1.343 (14)
1.389 (13)
1.375 (12)
C(32)
C(34)
C(41)
C(33)
C(35)
C(45)
1.361 (14)
1.382 (12)
1.387 (11)
C(33)
C(35)
C(41)
C(34)
C(36)
C(46)
1.374 (13)
1.382 (11)
1.386 (11)
C(42)
C(43)
C(43)
C(44)
1.385 (12)
1.368 (12)
C(42)
C(44)
C(46)
C(45)
1.408 (12)
1.380 (12)
C(51)
C(52)
1.387 (13)
C(51)
C(56)
1.411 (11)
C(52)
C(54)
C(53)
C(55)
1.361 (14)
1.385 (13)
C(53)
C(55)
C(54)
C(56)
1.372 (13)
1.386 (12)
C(61)
C(62)
1.394 (14)
C(61)
C(66)
1.391 (12)
C(62)
C(64)
C(63)
C(65)
1.335 (15)
1.408 (14)
C(63)
C(65)
C(64)
C(66)
1.354 (14)
1.377 (12)
C(71)
C(72)
1.396 (13)
C(71)
C(76)
1.389 (13)
C(72)
C(74)
C(73)
C(75)
1.367 (14)
1.397 (12)
C(73)
C(75)
C(74)
C(76)
1.355 (14)
1.399 (12)
C(81)
C(82)
C(84)
C(82)
C(83)
C(85)
1.390 (12)
1.378 (12)
1.365 (12)
C(81)
C(83)
C(85)
C(86)
C(84)
C(86)
1.391 (11)
1.377 (12)
1.404 (11)
187
Table 32 Intramolecular bond angles () for 11, involving the non-hydrogen atoms.
Atom
Atom
Atom
Angle
Atom
Atom
Atom
Angle
0(1)
Si(1l)
0(2)
112.6 (3)
0(1)
Si(l)
C(16)
103.7 (3)
0(2)
0(2)
Si(l)
Si(l)
C(16)
C(86)
112.4 (3)
103.3 (3)
0(1)
C(16)
Si(l)
Si(l)
C(86)
C(86)
110.3 (3)
114.8 (4)
C(3)
C(4)
Si(2)
Si(2)
C(4)
C(46)
111.4 (4)
109.1 (4)
C(3)
C(3)
Si(2)
Si(2)
C(46)
C(56)
104.0 (3)
111.8 (4)
C(4)
Si(2)
C(56)
109.5 (4)
C(46)
Si(2)
C(56)
110.8 (4)
Si(1l)
C(2)
C(66)
0(1)
Si(2)
0(1)
C(1)
C(1)
C(2)
C(3)
C(2)
C(66)
C(76)
C(3)
C(2)
129.3
118.7
115.8
113.1
117.5
(5)
(7)
(7)
(7)
(5)
Si(1l)
C(2)
0(1)
C(1)
Si(2)
0(2)
C(1)
C(2)
C(2)
C(4)
C(5)
C(76)
C(1)
C(3)
C(5)
132.9
125.4
119.7
127.2
113.8
0(2)
C(4)
C(5)
C(5)
C(5)
C(6)
C(4)
C(6)
C(36)
114.6 (7)
126.3 (8)
118.0 (7)
0(2)
C(5)
C(26)
C(5)
C(6)
C(6)
C(6)
C(26)
C(36)
118.7 (7)
126.7 (7)
115.4 (7)
Si(1l)
C(6)
C(6)
Si(2)
Si(2)
C(1)
C(1)
Si(1l)
C(16)
C(26)
C(36)
C(46)
C(56)
C(66)
C(76)
C(86)
C(15)
(25)
C(35)
C(42)
C(55)
C(65)
C(75)
C(85)
121.5
117.4
119.4
122.8
122.2
123.4
120.6
121.8
Si(1l)
C(6)
C(6)
Si(2)
Si(2)
C(1)
C(1)
Si(l)
C(16)
C(26)
C(36)
C(46)
C(56)
C(66)
C(76)
C(86)
C(11)
C(21)
C(31)
C(41)
C(51)
C(61)
C(71)
C(81)
120.5
124.4
121.6
120.1
121.6
118.2
122.2
121.2
(6)
(7)
(7)
(6)
(6)
(7)
(8)
(6)
(5)
(7)
(7)
(7)
(5)
(7)
(8)
(7)
(6)
(6)
(8)
(8)
(6)
188
Preparation of 1,1-Diphenylacetone Dianion [Ph2 CC(O)CH2] 2 - (1) (TW.I-
72, II-6)
1,1-Diphenylacetone dianion, [Ph2CC(O)CH 2 ] 2 - (1), was prepared according to a
literature procedure. 3 A 100 mL round-bottomed Schlenk flask equipped with a magnetic
stir bar and a rubber septum was charged with 0.5 g (12.5 mmol) of potassium hydride and
50 mL of THF. A solution of l,l-diphenylacetone (2.62 g, 12.5 mmol) in 10 mL of THF
was added slowly to the flask by cannula. Hydrogen gas evolution was observed. After
stirring at room temperature for 15-20 min, a clear orange solution was obtained. To this
orange solution at 0°C, one molar equivalent of n-butyllithium was added (4.93 mL of a
2.53 M solution). The resulting red mixture was stirred at 0°C under argon for 5-7 min., at
which point it was ready for further reaction.
Preparation of 1,1,5,5-Tetramethyl-3,7-bis(diphenylmethylene)-1,5-disila2,8-dioxacyclooctane
(5) (TW-11-13, TW-III-69,
71).
A 250 mL round-bottomed Schlenk flask equipped with a magnetic stir bar and a
rubber septum was charged with 1.61 g (12.5 mmol) of Me2SiCl2 and 100 mL of THF.
To this solution at 0° C was added slowly by cannula 12.5 mmol of 1,1-diphenylacetone
dianion 1 in 50 mL of THF. The resulting mixture was stirred at room temperature for 5 h.
A yellow suspension was obtained. All volatiles were removed by evaporation under
reduced pressure, and the resulting residue was extracted with hexane (3 x 100 mL).
Filtration under nitrogen through Celite gave a pale yellow filtrate. The filtrate was
concentrated to about 30 mL under reduced pressure and stored at -23C for 2 days.
Compound 5 was obtained as a colorless, air-stable needle, 2.3 g (69%), after
recrystallization from hexane, mp 145-147C.
1H
NMR (300 MHz, CDCI 3 ): 8 -0.04 (s, 6 H, CSi(CH 3 ) 2 ), 0.14 ( s, 6 H, OSi(CH 3) 2 ),
2.01 (s, 4 H, CH2), 7.06-7.32 (m, 20 H, Ph).
189
13 C
NMR (75.4 MHz, CDC13): 8 -2.7 (q, J = 118.8 Hz, CSi(CH3 )2 ), -2.3 (q, J = 119.7
Hz, OSi(CH3 )2), 24.7 (t, J = 121.1 Hz, CH2 Si(CH3 )2), 120.5 (s,
CH 2 C=CPh 2 ), 125.3-146.2(m, Ph), 146.9 (t, 2J = 5.8 Hz, CH2C--CPh2 ).
29 Si
NMR (59.59 MHz, CDC13): 6 -6.2 (CSiMe2 ), 3.4 (OSiMe2 ).
MS (EI); Calcd. for C34H36 Si20 2 : 532; Found: m/z (fragment. relative intensity): 532
(M+ , 53), 503 (M+ - 2CH3, 2), 365 (M+ - CPh2, 11), 340 (M+ - Ph2C=CCH2,
21), 282 (M+ - Ph2C=CCH2SiMe2, 6), 210 (18), 192 (Ph2C=CCH2+ , 100),
182 (96), 166 (CPh2, 90), 152 (57), 77 (Ph, 83),
IR (KBr, cm-1): 2977(s), 2932(w), 2864(s), 1580(m), 1444(m), 1382(m), 1350(m),
1123(s), 1077(s, Si-O), 1005(w), 840(w), 833(w), 702(m).
Anal. Calcd. for C34H36 Si2 02: C, 76.64; H, 6.81. Found: C, 76.60; H, 7.03.
Mol wt. (VPO, CHC13):Calcd. for C34H36 Si202: 532; Found: 545.
Three different concentrations of 5 were prepared and A V values were
determined. The data was given in Table 33. A plot of A V/C versus C (Figure 19)
was prepared and the zero concentration intercept was used to calculate the molecular
weight. The extrapolated value is 5.36. The molecular weight is then calculated to be
4492/5.36 = 838 g/mol.
190
Table 33. Determination of molecular weight of 5
Reading
(microvolts)
Concentration
(mg/mL)
1.1
11.01
3.3
6.4
28.57
52.62
AV/C
AV
(solution-solvent)
8.19
8.05
9.01
26.57
50.62
7.91
8.4
8.3
8.2
8.1
*A
8.0
7.9
7.8
1
2
3
4
5
6
C
Figure 19.
VPO data for 5
7
V/C
191
Preparation of 1,1,5,5-Tetraethyl-3,7-bis(diphenylmethylene)l1,5-disila2,8-dioxacyclooctane
(6) (TW-III-67,
75).
A THF solution containing 12.5 mmol of dianion 1 was added dropwise to
Et 2 SiCI 2 (1.96 g, 12.5 mmol) in 100 mL of THF at 0°C. The resulting mixture was stirred
at room temperature for 5 h. A yellow suspension was obtained. All volatiles were
removed by evaporation under reduced pressure, and the resulting residue was extracted
with hexane (3 x 100 mL). Filtration under nitrogen through Celite left a yellow filtrate.
The filtrate was concentrated to about 10 mL under reduced pressure and stored at -23°C.
Compound 6 was obtained as colorless, air-stable crystals, 2.1 g (56%), after
recrystallization twice from hexane at -23C(, mp 110-1120 C.
1H
NMR (300 MHz, CDC13 ): 8 0.43 (q, 4 H, J = 7.8 Hz, CSiCH 2 CH 3), 0.57 (q, 4 H,
J = 7.6 Hz, OSiCH2CH3 ), 0.68 (t, 6 H, J = 7.8 Hz, CSiCH2CH 3), 0.79 (t, 6
H, J = 7.6 Hz, OSiCH2CH3 ), 2.09 (s, 4 H, CH2), 7.06-7.33 (m, 20 H, Ph).
13 C
NMR (75.4 MHz, CDC13): 6 3.9 (m, SiCH 2CH 3), 4.9 (m, SiCH 2CH 3 ), 5.9 (m,
SiCH2CH3 ), 7.0 (m, SiCH2CH3), 21.3 (t, J = 120.5 Hz, CH2 SiCH 2 CH 3),
120.4 (s, CH2 C=CPh 2), 125.2-142.3(m, Ph), 147.4 (t, 2 J = 5.9 Hz,
CH2C=CPh 2).
2 9 Si
NMR (59.59 MHz, CDC13 ): 86-7.46 (CSi), 7.25 (OSi).
MS (EI); Calcd. for C3 8H44Si202:588; Found: m/z (fragment, relative intensity): 588
(M + , 31), 421 (M + - Ph2C, 5), 396 (M + - Ph2C=CCH2, 15), 380 (M +
Ph2C=C(O)CH2,
119 (16), 115 (6).
-
3), 349 (3), 192 (Ph2C=CCH2 + , 100), 155 (8), 147 (20),
192
IR (KBr, cm-1): 3054(w), 3024(w), 2954(m), 2876(m), 1619(m,), 1494(w),
1457(w), 1442(w), 1221(s), 1196(m), 1150(m), 1072(w), 1004(s, Si-O),
909(m), 815(w), 767(s), 697(s).
Anal. Calcd. for C38 H44Si2 O 2: C, 77.49; H, 7.55. Found: C, 77.40; H, 7.55.
Mol wt. (VPO, CHC13): Calcd. for C38H44Si202: 588; Found: 618.
Preparation of 1,5-Dihydrido-1,5-dimethyl-3,7 bis(diphenylmethylene)1,5-disila-2,8-dioxacyclooctane
(7) (TW-III-66,
68).
A THF solution containing 12.5 mmol of dianion 1 was added dropwise to
MeHSiC12 (1.43 g, 12.5 mmol) in 100 mL of THF at 0°C. The resulting mixture was
stirred at room temperature for 5 h. A pale yellow suspension was obtained. All volatiles
were removed by evaporation under reduced pressure, and the resulting residue was
extracted with hexane (3 x 100 mL). Filtration under nitrogen through Celite gave a pale
yellow filtrate. The filtrate was concentrated to about 40 mL under reduced pressure and
stored at -230 C for 2-3 days. Compound 7 was obtained as a colorless, air-stable solid,
2.2 g (70%), after recrystallization from hexane, mp: 180-182°C.
1H
NMR (300 MHz, CDC13 ): 8 0.10 (d, 3 H, 3 J = 3.6, SiHCH 3), 0.16 (d, 3 H, 3 =
1.5, OSiHCH 3), 2.05 (dd, 2 H, 2J = 14.2 Hz, 3J = 4.0 Hz, CHaHbSiHCH3),
2.18 (d, 2 H, 2 J = 14.2 Hz, CHaHbSiHMe), 4.05 (m, 1 H, CH2SiHCH3 ),
4.65 (d, 1 H, 3 = 1.5, OSiHCH3),
13 C
7.09-7.34 (m, 20 H, Ph).
NMR (75.4 MHz, CDC13 ): 8 -5.3 (dq, J = 122.2 Hz, 2J = 18.7 Hz, CSiHCH3 ),
-2.6 (dq, J = 119.5 Hz, 2 = 17.3 Hz, OSiHCH 3 ), 21.7 (t, J = 114.5 Hz,
193
CH2SiHCH 3), 121.4 (s, CH2C=CPh2), 124.6-141.9 (m, Ph), 146.4 (s,
CH2C=CPh2).
29Si NMR (59.59 MHz, CDC13): 8 -21.2 (d, JSi-H = 203 Hz, CSi), -10.4 (d, JSi-H =
262 Hz, OSi).
MS (EI); Calcd. for C32H32Si202:504; Found: m/z (fragment, relative intensity): 504
(M+, 34), 312 (M + - Ph2C=CCH2, 23), 293 (6), 233 (7), 192 (Ph2C=CCH2 + ,
100), 166 (CPh2, 20), 119 (57), 91 (17).
IR (KBr, cm-l): 3124(w), 3005(w), 2985(w), 2916(w), 2200(m, Si-H), 2122(m, Si-H),
1636(m), 1492(m), 1441(m), 1243(s), 1223(s), 1207(m), 1118(s), 1072(s, Si-
0), 1033(w), 930(w), 916(m), 864(s), 784(m), 761(s), 742(m), 698(s).
Anal. Calcd. for C32H32Si202: C, 76.14; H, 6.39. Found: C, 75.99; H, 6.45.
Mol. wt. (VPO, CHC13):Calcd. for C32 H32Si202: 504; Found: 534.
Preparation of 1,1,5,5-Tetraphenyl-3,7-bis(diphenylmethylene)-1,5-disila2,8-dioxacyclooctane
(8) (TW-IV-30).
A THF solution containing 12.5 mmol of dianion 1 was added dropwise to
Ph2SiCI2(3.16 g, 12.5 mmol) in 100 ml of THF at 0°C. During the addition, the red color
of the dianion was discharged slowly. Upon completion of the dianion addition, the
resulting mixture was stirred at room temperature overnight. A yellow suspension was
obtained. All volatiles were removed by evaporation under reduced pressure, and the
resulting residue was extracted with hexane (3 x 100 mL). Filtration under nitrogen
through Celite gave a yellow filtrate. The filtrate was evaporated under reduced pressure.
194
Compound 7 was obtained as a colorless, air-stable solid, 2.0 g (40%), after
recrystallization from dichloromethane and hexane at -230 C for one week, mp 189-191°C.
Single crystals of X-ray quality were obtained by dissolving 8 in methylene chloride and
allowing the solution to evaporate slowly.
1H
NMR (300 MHz, CDC13 ): 8 2.62 (s, 4 H, CH2 ), 6.61-7.42 (m, 40 H, Ph).
13 C
NMR (75.4MHz, CDC13 ): 8 22.8 (t, J = 122.0 Hz CH2 SiPh2 ), 122.5 (s,
CH2C=CPh 2 ), 125.7-141.2 (m, Ph), 145.4 (t, 2 J = 5.8 Hz, CH2C--CPh2).
29Si NMR (59.59 MHz, CDC 3 ): 8 -36.6 (CSi), -9.4 (OSi).
MS (EI); Calcd. for C54H44Si202:780; Found: m/z (fragment, relative intensity): 780
(M + , 18). 588 (M + - Ph 2 C--CCH 2 , 17), 493 (14), 397 (16), 319 (28),
259(15), 216 (23), 192 (Ph2C--CCH2 + , 100), 177 (5), 115 (4).
IR (KBr, cm-1 ): 3051(w), 3026(s), 2898(w), 1643(m), 1619(m), 1598(w), 1492(w),
1426(s), 13954(w), 1218(s), 1187(w), 1146(w), 111lll(s), 1077(s, Si-O),
1070(w), 1004(s), 962(w), 853(w), 768(m), 723(w).
Anal.: Calcd. for C5 4H44Si202 : C, 83.03; H, 5.68. Found: C, 82.72; H, 5.76.
Mol. wt.: (VPO, CHC13)Calcd. for C54H44Si202: 780; Found: 830.
195
Preparation of 1,1,5,5-Tetraethyl-3,7-bis(diphenylmethylene)-1,5-disila2,6-dioxacyclooctane
(9) (TW.V-3,
TW-VI-12).
A THF solution containing 12.5 mmol of dianion 1 was added dropwise to Et2 SiF2
(1.96 g, 12.5 mmol) in 100 mL of THF at 0°C. The red color of the dianion was
discharged quickly at the beginning of the reaction. As the addition progressed, the red
color of the dianion was discharged very slowly. Upon completion of the dianion addition,
the resulting mixture was stirred at room temperature overnight. A red suspension was
obtained. All volatiles were removed by evaporation under reduced pressure, and the
resulting residue was extracted with hexane (3 x 100 mL). Filtration under nitrogen
through Celite gave a yellow filtrate. The filtrate was concentrated to about 10 mL under
reduced pressure and stored at -23°C. Compound 9 was obtained as colorless, air-stable
crystals, 1.7 g (47%), after recrystallization twice from hexane at -23 0 C, mp 84-860 C.
1H
NMR (300 MHz, CDC13 ): 8 0.62 (m, 8 H, SiCH2 CH 3), 0.84 (t, 12 H, J = 7.8,
SiCH2CH3), 2.10 (s, 4 H, CH2), 7.23-7.38 (m, 20 H, Ph).
1 3C
NMR (75.4 MHz, CDC13): 8 5.8 (m, SiCH 2 CH 3 ), 6.1 (m, SiCH2 CH3 ), 23.8 (t,
J = 120.5 Hz, CH2SiCH2CH3), 120.3 (s, CH2C=CPh2), 123.9-142.5(m,
Ph), 146.7 (t, 2 J = 5.9 Hz, CH 2 C=CPh2).
2 9 Si
NMR (59.59 MHz, CDC13): 8 13.6.
MS (El); Calcd. for C38H44Si2O2: 588; Found: m/z (fragment, relative intensity): 588
(M + , 35), 486 (M+- Et2SiO, 4), 396 (M+- Ph2C=CCH2, 30), 380 (M + Ph2C=C(O)CH2,
18), 294 (0.5M + , 18), 247 (5), 192 (Ph2C=CCH2 + , 100),
147 (18), 119 (10).
196
IR (KBr, cm-l1 ): 3056(wO, 3028(w), 2951(mO, 2872(m), 1622(s), 1596(m), 1574(w),
1494(m), 1458(w), 1442(m), 1407(w), 1386(w), 1231(broad, s), 1196(m),
1160(w), 1126(m), 1071(w), 995(s, Si-O), 907(m), 866(w), 845(s), 794(s).
Anal. Calcd. for C38H44Si202: C, 77.49; H, 7.55. Found: C, 77.39; H, 7.58.
Mol wt. (VPO, CHC13):Calcd. for C3 8H44Si202: 588; Found: 603.
Preparation of 1,1,5,5-Tetraphenyl-3,7-bis(diphenylmethylene)-1,5-disila2,6-dioxacyclooctane
(10) (TW-IV-17, 22).
A THF solution containing 12.5 mmol of dianion 1 was added dropwise to
Ph2 SiF2 (2.75 g, 12.5 mmol) in 100 ml of THF at 0°C. The red color of the dianion was
discharged very slowly. Upon completion of the dianion addition, the resulting mixture
was stirred at room temperature overnight. A red suspension was obtained. All volatiles
were removed by evaporation under reduced pressure, and the resulting residue was first
extracted with hexane (2 x 100 mL), and then with toluene (3 x 50 mL). Filtration of the
hexane extracts under nitrogen through Celite gave an orange solution. A yellow polymeric
mixture (2.5 g), which has a molecular weight range from 500-2400 by GPC, was
obtained after removing hexane under reduced pressure. The 29 Si NMR of this mixture
showed 4-5 signals which were very weak and difficult to identify. Filtration of the
toluene extracts under nitrogen through Celite gave a yellow filtrate. The filtrate was
evaporated under reduced pressure. Compound 10 was obtained as colorless, air-stable
crystals, 1.0 g (21%), after recrystallization from dichloromethane and hexane, mp 2392400 C. Single crystals of X-ray quality were obtained by dissolving compound 10 in a
minimum amount of methylene chloride, adding two equivalents of hexane, and storing the
resulting solution at -23 0 C.
197
1H
NMR (300 MHz, CDC13): 8 2.56 (s, 4 H, CH2), 6.71-7.38 (m, 40 H Ph).
13C NMR (75.4MHz, CDC13 ): 8 24.4(t, J = 120.4 Hz, CH2 SiPh2 ), 122.3 (s,
CH 2 C=CPh 2 ), 124.4-141.7 (m, Ph), 144.8 (t, 2 J = 5.8 Hz, CH2C=CPh2).
2 9 Si
NMR (59.59 MHz, CDC13 ): 8 -10.7.
MS (EI); Calcd. for C4H44Si2O2: 780; Found: m/z (fragment, relative intensity): 780
(M+ , 25). 588 (M+-Ph2C=CCH2, 8), 494 (20), 415 (7), 397 (14), 390 (0.5
M+ , 9), 319 (31), 257 (5), 192 (Ph2C=CCH2 + , 100), 115 (5).
IR (KBr, cm-1): 3045(w), 3030(w), 3992(w), 1629(m), 1493(m), 1427(s), 1241(s),
1156(w), 1136(w), 1121(s), 1101(w), 1050(w), 1005(s, Si-O), 910(w),
763(w), 731(m), 714(m), 697(s), 529(w).
Anal. Calcd. for C5 4H44Si202 : C, 83.03; H, 5.68. Found: C, 82.79; H, 5.72.
Mol. wt. (VPO, CHC13): Calcd. for C4H44Si202: 780; Found: 813.
Preparation of 1,1,2,2,6,6,7,7-Octamethyl-4,9-bis(diphenylmethylene)1,2,6,7-tetrasila-3,10-dioxacyclodecane (11) (TW-III-48, 50, 52; TW-IV-
7).
A THF solution containing 12.5 mmol of dianion 1 was added dropwise to
C1SiMe2Me2SiCl(2.32 g, 12.5 mmol) in 100 mL of THF at 0°C. The resulting mixture
was stirred at room temperature overnight. A yellow suspension was obtained. All
volatiles were removed by evaporation under reduced pressure, and the resulting residue
was subsequently extracted with hexane (3 x 100 mL). Filtration under nitrogen through
198
Celite gave a pale yellow filtrate. The filtrate was concentrated to about 40 mL under
reduced pressure and stored at -230 C. Compound 11 was obtained as colorless, air-stable
crystals, 2.7 g (67%), after recrystallization from hexane, mp 132-134°C Single crystals of
X-ray quality were obtained by dissolving 11 in hexane and letting the solution stand at
room temperature for two days.
1H
NMR (300 MHz, CDC13): 8 0.02(s, 12 H, SiMe2SiMe2 ), 0.05( s, 12 H,
SiMe2SiMe2), 1.99 (s, 4 H, CH2), 7.01-7.35 (m, 20 H, Ph).
1 3C
NMR (75.4MHz, CDC13): 8 -3.2 (q, J = 119.8 Hz, SiMe2 SiMe2), -3.1 (q, J =
119.9 Hz, SiMe2SiMe2), 24.9 (t, J = 122.0 Hz, CH2), 121.5 (s,
CH2C=CPh2),
125.2-142.8 (m, Ph), 149.0(t, 2 J = 6.0 Hz, CH2C--CPh2).
29Si NMR (59.59 MHz, CDC13 ): 8 -14.7 (CSi), 10.0 (OSi).
MS (EI); Calcd. for C38H48Si204: 648; Found: m/z (fragment, relative intensity): 648
(M + , 42). 456 (M+-Ph2C--CCH2, 1), 324 (0.5M + , 13), 233
(PhC=COSiMe2SiMe2
+,
31), 192 (Ph2C=CCH2 + , 100). 147 (35), 133
(Me2SiMe2SiO + , 41), 117 (Me2SiSiMe2 + , 21), 73 (100)
IR (KBr, cm-1): 3075(w), 3017(w), 2950(m), 2921(m), 1615(m), 1594(m), 1492(s),
1468(w), 1441(m), 1398(w), 1247(m), 1225(s), 1189(m), 1135(m), 1108(s),
1071(w), 1032(w), 971(s, Si-O), 926(w), 854(m), 830(s), 819(s), 792(s),
697(s).
Anal. Calcd. for C38H48 Si2 04: C, 70.31; H, 7.45. Found: C, 70.27; H, 7.46.
199
Mol. wt. (VPO, CHC13): Calcd. for C38H48Si204: 648; Found: 672.
Preparation of 1,1,2,2,3,3-Hexamethyl-5-diphenylmethylene-1 ,2,3-trisila4-oxacyclohexane
(12) (TW-III-56, 61, 70; TW-IV-10).
A THF solution containing 12.5 mmol of dianion 1 was added dropwise to one
equivalent of 1,3-dichlorohexamethyltrisilane(3.05 g, 12.5 mmol) in 100 mL of THF at
0°C. The resulting mixture was stirred at room temperature overnight. A pale yellow
suspension was obtained. All volatiles were removed by evaporation under reduced
pressure, and the resulting residue was subsequently extracted with hexane (3 x 100 ml).
Filtration under nitrogen through Celite gave a pale yellow filtrate. All volatiles were
removed under reduced pressure, and a yellow, viscous, oily mixture was obtained. A
colorless, air-stable solid was obtained after Kugelrohr distillation of the oily mixture at
0.01 mm Hg with heating to 1030 C-1300 C. Compound 12 was obtained as colorless, air
stable crystals, 3.0 g (62%), after recrystallization from hexane at -230 C, mp 94-96°C.
1H
NMR (300 MHz, CDC13 ): 8 0.08 (s, 6 H, CH2 Si(CH3 )2 ), 0.16 ( s, 6 H, Si(CH3 )2 ),
0.19 (s, 6 H, OSi(CH3)2), 1.82 (s, 2 H, CH2), 7.03-7.29 (m, 10 H, Ph).
13 C
NMR (75.4MHz, CDC13 ): 8 -7.8 (q, J = 120.0 Hz, Si(CH3 )2 ), -3.1 (q, J = 117.0
Hz, Si(CH3)2), 1.0 (q, J = 120.0 Hz, Si(CH3 )2), 24.3 (t, J = 121.4 Hz, CH2),
119.5 (s, CH2C=CPh2), 123.8-142.8 (m, Ph), 149.3(t, 2j = 6.0 Hz,
CH2C=CPh2).
2 9 Si
NMR (59.59 MHz, CDC1 3 ): 8 -56.1 (CH2SiMe2), -17.9 (SiMe 2 ), 19.4 (OSiMe2).
MS (El); Calcd. for C21H3 0Si3 0: 382; Found: m/z (fragment, relative intensity): 382 (M+ ,
49), 367 (M+- Me, 9), 324 (M+- SiMe2, 9), 233 (PhC=COSiMe2SiMe2+,
200
27), 192 (Ph 2 C=CCH2 + , 100), 174 (Me2SiMe2SiSiMe2 + , 55), 132
(Me2SiMe2SiO + , 81), 116 (Me2SiSiMe2+ , 56), 73 (100)
IR (KBr, cm-l1 ): 3054(w), 3025(w), 2950(m), 2891(w), 1614(broad, m), 1584(w),
1494(m), 1400(w), 1441(m), 1400(w), 1246(s), 1225(m), 1190(w), 1115(w),
1032(w), 979(m, Si-O), 899(w), 829(s), 779(s), 699(s), 649(w).
Anal. Calcd. for C21H3 0Si3 0: C, 65.90; H, 7.90. Found: C, 66.03; H, 7.91.
Mol. wt. (VPO, CHC13):Calcd. for C21 H30 Si3 0: 382; Found: 399.
Preparation of Ph2CHC(=O)CH2 SiMe2CH2C(=O)CHPh2 (13) (TW-III-72).
A 100 mL round-bottomed Schlenk flask equipped with a magnetic stir bar and
a rubber septum was charged with 0.35 g of 5 (0.66 mmol) and 50 mL of Et2O. To this
solution at 0° C was added, dropwise with stirring, two molar equivalents of methyllithium
as a complex with lithium bromide (0.88 mL, 1.5 M in diethyl ether). The resulting
mixture was stirred at 0°C for 30 minutes, and then stirred at RT for approximately one
hour. A solution of saturated aqueous ammonium chloride was added to quench the
reaction. The organic layer was separated and the aqueous layer was extracted twice with
Et20 and the combined organic layers were washed twice with water. The organic layer
was dried over MgSO4 and all volatile were removed using a rotary evaporator to leave 13
as a colorless solid compound. Further purification by recrystallization from hexane at 230 C yielded colorless, air-stable crystals of 13, 0.25 g (80%), mp 79-81°C.
1H NMR (300 MHz, CDC13): 8 0.16 (s, 6 H, SiMe2 ), 2.33 (s, 4 H, CH2 ), 5.11 (s, 2
H, CHPh2), 7.20-7.35 (m, 20 H, Ph).
201
13 C
NMR (75.4MHz, CDC13): 8 -1.9 (q, J = 120.3 Hz, SiMe2), 36.1 (t, J = 122.1 Hz,
CH2), 65.7 (d, J = 127.0 Hz, CHPh2), 127.0-138.3 (m, Ph), 206.2(s, C=O).
29Si NMR (59.59 MHz, CDC13):8 2.68.
MS (EI); Calcd. for C3 2H32SiO2:476; Found: m/z (fragment, relative intensity): 476 (M+,
1), 309 (M + - Ph2C, 19), 267 (M+ - Ph2CHCOCH2, 100), 192 (Ph2C=CCH2,
55), 167 (Ph2C + , 100), 152 (35), 135 (82), 115 (60), 75 (70).
IR (KBr, cm-l): 3025(w), 3008(w), 2920(w), 1693(s, C=O), 1598(w), 1493(m),
1451(w), 1403(w), 1253(w), 1186(w), 1113(w), 1040(w), 843(m), 745(w),
699(s), 599(w).
Anal. Calcd. for C3 2H3 202Si: C, 80.63; H, 6.77. Found: C, 80.63; H, 6.81.
Preparation of Ph2 CHC(=CH2)OSiMe
III-58,
2 SiMe2OC(=CH2)CHPh2
(14) (TW-
64, 73).
A 100 mL round-bottomed Schlenk flask equipped with a magnetic stir bar and a
rubber septum was charged with 0.36 g of 11 (0.56 mmol) and 50 mL of Et2O. To this
solution at 0 ° C was added dropwise with stirring two molar equivalents of methyllithium as
a complex with lithium bromide (0.74 mL, 1.5 M in diethyl ether). The resulting mixture
was stirred at 0°C for 30 minutes, and then stirred at room temperature for approximately
one hour. A solution of saturated aqueous ammonium chloride was added to quench the
reaction. The organic layer was separated and the aqueous layer was extracted twice with
Et20 and the combined organic layers were washed twice with water. The organic layer
was dried over MgSO4 and all volatile were removed using a rotary evaporator to leave 14
202
as a colorless solid compound. Further purification by recrystallization from hexane at 230 C yielded colorless, air-stable crystals of 14, 0.18 g (60%), mp 88-90 0 C.
1H
NMR (300 MHz, CDC13 ): 8 0.06 (s, 12 H, SiMe 2), 3.93 (d, 2 H, 2 J = 1.5 Hz,
CHaHb), 4.14 (d, 2 H, 2 J = 1.5 Hz, CHaHb), 4.63 (s, 2 H, CHPh2), 7.14-
7.25 (m, 20 H, Ph).
13C
NMR (75.4MHz, CDC1 3): 8 -0.6 (q, J = 120.0 Hz, SiMe2), 58.1 (d, J = 127.4 Hz,
CHPh2), 92.8 (t, J = 156.1 Hz, C=CH 2 ), 126.3-141.7 (m, Ph), 160.3 (t,
2
= 3.6 Hz, C=CH2).
29Si NMR (59.59 MHz, CDC13 ): 6 10.65.
MS (EI); Calcd. for C34H3802Si2: 534; Found: m/z (relative intensity): 534 (M+ , 3), 325
(M+-Ph 2 CHC=CH 2 0, 34), 267 (0.5M + , 100), 209 (Ph2CHC--CH20
192 (Ph 2 CHC=CH
+
2 ,
+,
11),
94), 178 (21), 135 (80), 115 (65), 91 (42), 75 (38).
IR (KBr, cm-1): 3052(w), 3025(m), 2952(w), 2901(w), 1626(s), 1598(w), 1494(s),
1449(m), 1380(w), 1290(w), 1275(s), 1248(s), 1214(s), 1090(w), 1008(s),
920(w), 903(w), 826(w), 787(w), 740(w), 697(s).
Anal. Calcd. for C34 H3 80 2 Si2 : C, 76.35; H, 7.16. Found: C, 76.28; H, 7.22.
Preparation of Ph2 C=C(CH 3)OSiMe3 (17a) (PL).
A 100 mL round-bottomed Schlenk flask equipped with a magnetic stir bar and a
rubber septum was charged with 0.5 g (12.5 mmol) of potassium hydride and 50 mL of
THF. A solution of 1,-diphenylacetone (2.62g, 12.5mmol) in 10 mL of THF was slowly
203
added to the flask by cannula. Hydrogen gas evolution was observed. After stirring at
room temperature for 15-20 minutes, a clear orange solution was obtained. To this orange
solution at 0°C was added one molar equivalent of Me3SiCI (1.36 g, 12.5 mmol). The
resulting mixture was stirred at RT for 10 h to give a yellow solution. All volatiles were
removed under reduced pressure and the residue was extracted with 3 x 100 mL of hexane.
Filtration through Celite was followed by removal of volatiles at reduced pressure to yield a
yellow crude product. Distillation of the crude product afforded 2.78 g of 17a as a clear,
colorless oil, 2.78 g (79%), bp 96°C/0.05 mm Hg. The product identity was confirmed by
comparison of the 1H NMR spectrum with that reported in the literature. 9
1H
NMR (300 MHz, CDC13): 8 0.03 (s, 9 H, SiMe 3), 1.90 (s, 3 H, CH 3 ), 7.23 (m, 10
H, Ph).
MS (EI) m/z (fragment, relative intensity): 282 (M+ , 82), 267 (M+ - Me, 26), 252 (M+ 2 Me, 7), 73 (SiMe, 100)
IR (thin film, cm-1l): 3057(m), 3026(m), 2956(s), 1662(m), 1629(s), 1599(m), 1576(m),
1494(s), 1443(s), 1376(s), 1252(s), 1187(s), 1027(s), 1002(s), 986(s).
Preparation of Ph2C=C(CH3)OSiMe2t-Bu (17b) (PL).
A 100 mL round-bottomed Schlenk flask equipped with a magnetic stir bar and a
rubber septum was charged with 0.5 g (12.5 mmol) of potassium hydride and 50 mL of
THF. A solution of 1,1-diphenylacetone (2.62g, 12.5 mmol) in 10 mL of THF was
slowly added to the flask by cannula. Hydrogen gas evolution was observed. After
stirring at room temperature for 15-20 minutes, a orange solution was obtained. To this
orange solution at 0°C was added one molar equivalent of tBuMe2SiCl (1.88 g, 12.5
mmol). The resulting mixture was stirred at RT for 10 h to give a yellow solution. All
204
volatiles were removed under reduced pressure and the residue was extracted with 3 x 100
mL of hexane. Filtration through Celite was followed by removal of volatiles at reduced
pressure to yield a yellow crude product. Distillation of the crude product afforded 2.92 g
(72%) of 17b as a clear, colorless oil, bp 1060 C/0.05 mm Hg.
1H
NMR (300 MHz, CDC13 ): 8 -0.03 (s, 6 H, SiMe2), 0.79 (s, 9 H, tBu), 1.93 (s, 3 H,
CH 3 ), 7.10-7.35 (m, 10 H, Ph).
13 C NMR (75.4MHz, CDC1 3): 8 -4.2 (SiMe), 18.2 (C(CH 3) 3), 21.6 (CH 3 ), 25.7
(C(CH3)3), 123.0 (C=CPh 2 ), 125.7-142.4 (Ph), 146.2 (C--CPh2).
2 9 Si
NMR (59.59 MHz, CDC13): 8 18.87.
IR (thin film, cm-l): 3075(m), 3015(m), 2965(s), 2910(m), 1615(s), 1490(s), 1440(s),
1400(m), 1380(m), 1270(s), 1230(s), 1190(s), 1150(m), 1105(s), 990(s).
Anal. Calcd. for C21H28OSi: C, 77.72; H, 8.70. Found: C, 77.68; H, 8.95.
Preparation of CH2=C(OSiMe3 )CHPh2 (18) (PL)
A 100 mL round-bottomed Schlenk flask equipped with a magnetic stir bar and a
rubber septum was charged with 2.1 mL of diisopropylamine (12.5 mmol) in 40 mL THF.
One molar equivalent of nBuLi (4.9 mL of a 2.53 M solution, 12.5 mmol) was added at
0°C and stirred for 10 min. A solution of 1,1-diphenylacetone (2.62g, 12.5mmol) in 10
mL of THF was added slowly to the stirred LDATHF solution at 0°C. After stirring at
room temperature for lh, a red solution was obtained. To this red solution at O'C was
added one molar equivalent of Me3SiCl (1.36 g, 12.5 mmol). The resulting mixture was
stirred at RT for 8 h to give a yellow solution. All volatiles were removed under reduced
205
pressure and the residue was extracted with 3 x 100 mL of hexane. Filtration through
Celite was followed by removal of volatiles at reduced pressure to yield a yellow crude
product. Distillation of the crude product afforded 3.0 g (86%) of 18 as a clear, colorless
oil, bp 105C/0.08 mm Hg.
1H
NMR (300 MHz, CDC13 ): S 0.03 (s, 9 H, SiMe3 ), 4.02 (d, 2 J = 2.1 Hz, 1 H,
C=CHaHb), 4.26 (d, 2 J = 2.1 Hz, 1 H, C=CHaHb),4.69 (s, 1 H, CHPh2),
7.14-7.30 (m, 10 H, Ph).
13 C
NMR (75.4MHz, CDC13): 6 0.00 (q, J = 120.0 Hz, SiMe), 58.2 (d, J = 135.0,
CHPh 2 ), 93.3 (t, J = 142.0, C=CH2), 126.3-141.8 (m, Ph), 159.9 (s,
C=CH2).
29Si NMR (59.59 MHz, CDC13 ): 8 17.31.
IR (thin film, cm-l): 3084(w), 3061(m), 3026(w), 2958(w), 1628(s), 1600(w), 1494(s),
1450(m), 1276(s), 1252(s), 1221(s), 1008(s), 854(w), 790(s), 761(m),
698(s).
Anal. Calcd. for C18H22OSi:C, 76.54; H, 7.85. Found: C, 76.34; H, 7.84.
Preparation of Ph2C=C(CHSiMe3)OSiMe
3
(19) (TW-IV-72)
A THF solution containing 12.5 mmol of dianion 1 was added dropwise to two
equivalents of Me3SiCl (2.71 g, 25 mmol) in 120 mL of THF at 0°C. The resulting mixture
was stirred at RT for 10 h to give a pale yellow solution. All volatiles were removed under
reduced pressure and the residue was extracted with 3 x 100 mL of hexane. Filtration
through Celite was followed by removal of volatiles at reduced pressure to yield a yellow
206
oil. This yellow oil was chromatographed on alumina using pentane as eluent. The
product, 19, was obtained as a clear, colorless oil, 3.1 g (71%).
1H
NMR (300 MHz, CDC1 3 ): 8 -0.09 (s, 9 H, SiMe 3 ), -0.01 (s, 9 H, OSiMe 3), 1.68 (s,
2 H, CH2), 7.05 (m, 10 H, Ph).
13C NMR (75.4MHz, CDC13 ): 8 0.21 (q, J = 119.4 Hz, CH2 Si(CH3 )3 ), 0.85 (q, J =
118.1 Hz, OSiMe3), 26.4 (t, J =121.9 Hz, CH2), 121.9 (s, C=CPh 2 ), 125.8143.5 (m, Ph), 149.6(s, C=CPh2).
29Si NMR (59.59 MHz, CDC13 ): 8 2.43 (CSi); 16.40 (OSi).
MS (EI); m/z (fragment, relative intensity): 354 (M + , 33), 281 (M+ - SiMe3, 26), 267 (M+
- CH2SiMe3, 20), 265 (M + - OSiMe 3 , 12), 73 (SiMe 3 , 100)
IR (thin filnr, cm-l): 3030(m), 2920(m), 1610(s), 1570(w), 1490(s), 1445(m), 1268(s),
1250(s), 980(s), 860(m), 850(s),
Anal. Calcd. for C21H300Si2: C, 71.12; H, 8.53. Found: C, 71.47; H, 8.70.
Preparation of Ph2C=C(CH2SiMe2H)OSiMe2H (20) (PL)
A THF solution containing 12.5 mmol of dianion 1 was added dropwise to two
equivalents of Me2HSiCI (2.36 g, 25 mmol) in 120 mL of THF at 0°C. The resulting
mixture was stirred at RT for 10 h to give a pale yellow solution. All volatiles were
removed under reduced pressure and the residue was extracted with 3 x 100 mL of hexane.
Filtration through Celite was followed by removal of volatiles at reduced pressure to yield a
207
yellow oil. Distillation of this yellow oil afforded 3.34 g (82%) of 20 as a clear, colorless
oil, bp 950 C/0.05 mm Hg
1H
NMR (300 MHz, CDC1 3 ): 8 0.09 (d, 3J = 1.5 Hz, 6 H, CSiMe2), 0.16 (d, 3J = 1.5
Hz, 6 H, OSiMe2), 1.88 (d, 3 J = 1.5 Hz, 2 H, CH2Si), 4.02 (m, 3 J = 1.5 Hz,
1 H, CH2SiHMe2), 4.57 (d, 3 J = 1.5 Hz, 1 H, OSiHMe2), 7.26 (m, 10 H,
Ph).
13 C
NMR (75.4MHz, CDC13 ): 8 -3.9, -1.3, 22.6, 121.7, 125.6, 126.1, 127.5, 128.2,
130.2, 130.8, 141.2, 142.6, 148.9.
29Si NMR (59.59 MHz, CDC13 ): 8 -11.08 (CSi); 5.02 (OSi).
MS (El); m/z (fragment, relative intensity): 326 (M+ , 40), 208 (M+ - 2SiMe2H, 100), 73
(SiMe3, 100)
IR (thin film, cm-1): 3055(m), 3025(m), 2957(s), 2928(m), 2125(s, SiH), 1621(s),
1598(m), 1493(s), 1442(s), 1252(s), 1229(s), 1194(s), 1116(s),
Anal. Calcd. for C19H26 OSi2: C, 69.88; H, 8.02. Found: C, 69.53; H, 7.96.
Preparation of Ph2C=C(CH2SiMes3)OSiMe2t-Bu(21) (PL)
To a THF solution containing 12.5 mmol of dianion 1 was added slowly Me3SiCl
(1.36 g, 12.5 mmol) by syringe at 0°C. The resulting mixture was stirred at 0°C for 10
min. The red color of the dianion was discharged and a yellow suspension was obtained.
To this yellow suspension was added slowly one equivalent of tBuMe2SiCl (1.88 g, 12.5
mmol) by syringe at 0°C. The resulting mixture was stirred at RT for 10 h to give a yellow
208
solution. All volatiles were removed under reduced pressure and the residue was extracted
with 3 x 100 mL of hexane. Filtration through Celite was followed by removal of volatiles
at reduced pressure to yield a yellow oil This yellow oil was chromatographed on alumina
using pentane as eluent. The product, 21, was obtained as a clear, colorless oil, 4.16 g
(84%).
1H
NMR (300 MHz, CDC13 ): 6 -0.08 (s, 9 H, SiMe3 ), 0.08 (s, 6 H, OSiMe2), 0.86 (s,
9 H, CMe3), 1.88 (s, 2 H, CH2Si), 7.23 (m, 10 H, Ph).
13C
NMR (75.4MHz, CDC13 ): 6 -4.2, -0.1, 18.2, 25.8, 26.1, 121.2, 125.3, 125.8,
127.1, 127.8, 130.4, 130.9, 142.2, 143.4, 149.8.
2 9 Si
NMR (59.59 MHz, CDC13 ): 8 6.85 (CSi), 22.87 (OSi).
IR (thin film, cm-1): 3055(m), 3025(m), 2955(m), 2929(s), 1615(s), 1574(m), 1493(s),
1471(s), 1442(s), 1361(s), 1250(s), 1230(s), 1114(s), 1002(s).
Anal. Calcd. for C24H36OSi2: C, 72.66; H, 9.15. Found: C, 72.54; H, 9.13.
Preparation of Ph2C=C(CH2SiMe3)OSiPh2Me (22) (PL) .
To a THF solution containing 12.5 mmol of dianion 1 was added slowly one
equivalent of Me3SiCl (1.36 g, 12.5 mmol) by syringe at 0°C. The resulting mixture was
stirred at 0° C for 10 min. The red color of the dianion was discharged and a yellow
suspension was obtained. To this yellow suspension was added slowly one equivalent of
MePh2SiCI (2.91 g, 12.5 mmol) by syringe at 0°C. The resulting mixture was stirred at
RT for 10 h to give a yellow solution. All volatiles were removed under reduced pressure
and the residue was extracted with 3 x 100 mL of hexane. Filtration through Celite was
209
followed by removal of volatiles at reduced pressure to yield a yellow oil. This yellow oil
was chromatographed on alumina using pentane as eluent. The product, 22, was obtained
as a clear, colorless oil, 4.24 g, 71%.
1H
NMR (300 MHz, CDC1 3): 8 -0.26 (s, 9 H, SiMe3), 0.16 (s, 3 H, OSiMe), 1.43 (s, 2
H, CH2Si), 7.05 (m, 20 H, Ph).
13C
NMR (75.4MHz, CDC1 3): 6 -0.64, 25.4, 121.8, 125.4, 125.9, 127.6, 127.7,
128.1, 129.7, 130.6, 131.0, 134.5, 135.7, 141.7, 143.0, 149.5.
29Si NMR (59.59 MHz, CDC13 ): 8 -4.22 (CSi), 2.85 (OSi).
IR (thin film, cm-l): 3055(m), 3020(m), 2955(m), 2924(s), 1616(s), 1575(m), 1493(s),
1442(s), 1250(s), 1232(s), 1194(m), 1116(s), 1073(m).
Anal. Calcd. for C31H34OSi2: C, 77.76; H, 7.16. Found: C, 77.83; H, 7.28.
Preparation of Ph2C=C(CH2SiMe3)OSiMe2H (23) (PL) .
To a THF solution containing 12.5 mmol of dianion 1 was added slowly one
equivalent of Me3SiCI (1.36 g, 12.5 mmol) by syringe at 0°C. The resulting mixture was
stirred at 0 ° C for 10 min. The red color of the dianion was discharged and a yellow
suspension was obtained. To this yellow suspension was added slowly one equivalent of
HMe2SiCI (1.18 g, 12.5 mmol) by syringe at 0°C. The resulting mixture was stirred at RT
for 10 h to give a yellow solution. All volatiles were removed under reduced pressure and
the residue was extracted with 3 x 100 mL of hexane. Filtration through Celite was
followed by removal of volatiles at reduced pressure to yield a yellow oil. Compound 23
210
was obtained as a clear, colorless oil after purification by preparative GC. The yield,
determined by GC, was 84%.
1H
NMR (300 MHz, CDC13): 8 0.03 (s, 9 H, SiMe3), 0.07 (d, 3j = 2.5 Hz, 6 H,
OSiMe2), 1.78 (s, 2 H, CH2Si), 4.52 (m, 3j = 2.5 Hz, 1 H, SiH), 7.25 (m,
10 H, Ph).
13 C
NMR (75.4MHz, CDC1 3 ): 8 -0.1, -0.08, 25.1, 120.8, 125.2, 125.8, 126.4, 127.2,
129.7, 130.4, 141.2, 142.8, 149.5.
29Si NMR (59.59 MHz, CDC13): 8 4.20 (CSi), 4.75 (OSi).
IR (thin film, cm-1 ): 3055(s), 2956(s), 2124(s, SiH), 1617(s), 1558(m), 1493(s),
1442(s), 1250(s), 1229(s), 1195(m, 1149(m), 1116(s), 988(m), 896(s).
Anal. Calcd. for C20H28OSi2:C, 70.53; H, 8.29. Found: C, 70.97; H, 8.18.
Preparation of PhzC=C(CH2SiMe2H)OSiMe2t-Bu (24) (PL) .
To a THF solution containing 12.5 mmol of dianion 1 was added slowly one
equivalent of HMe2SiCl (1.18 g, 12.5 mmol) by syringe at 0°C. The resulting mixture was
stirred at 0° C for 10 min. The red color of the dianion was discharged and a yellow
suspension was obtained. To this yellow suspension was added slowly one equivalent of
tBuMe2SiCl (1.88 g, 12.5 mmol) by syringe at 0°C. The resulting mixture was stirred at
RT for 10 h to give a pale yellow solution. All volatiles were removed under reduced
pressure and the residue was extracted with 3 x 100 mL of hexane. Filtration through
Celite was followed by removal of volatiles at reduced pressure to yield a yellow oil. This
211
yellow oil was chromatographed on alumina using pentane as eluent. The product, 24,
was obtained as a clear, colorless oil, 3.44 g (72%).
1H
NMR (300 MHz, CDC13): 8 -0.38 (d, 3j = 2.4 Hz, 6 H, CH2 Si(CH3 )2 ), -0.17 (s, 6
H, OSiMe2), 0.56 (s, 9 H, SiCMe3), 1.59 (d, 3 J = 2.4 Hz, 2 H, CH2Si), 3.72
(m,
3J
= 2.4 Hz, 1 H, SiH), 6.88 (m, 10 H, Ph).
13C NMR (75.4MHz, CDC1 3 ): 8 -4.3, -3.9, 18.1, 23.2, 25.8, 121.7, 125.4, 125.9,
127.5, 128.1, 130.6, 131.0, 141.8, 143.2, 148.9.
29 Si
NMR (59.59 MHz, CDC13 ): 8 -11.78 (CSi), 21.18(OSi).
IR (thin film, cm-l): 3055(m), 3025(m), 2956(s), 2896(s), 2129(s, SiH), 1616(s),
1574(m), 1493(s), 1471(s), 1228(m), 1193(s), 1115(s).
Anal. Calcd. for C23 H34 OSi2 : C, 72.18; H, 8.95. Found: C, 72.06; H, 8.91.
Preparation of PhzC=C(CH2SiMe2t-Bu)OSiMe
2H
(25) (PL)
To a THF solution containing 12.5 mmol of dianion 1 was added slowly one
equivalent of tBuMe2SiCl (1.88 g, 12.5 mmol) by syringe at 0°C. The resulting mixture
was stirred at 0 ° C for 3 h. The red color of the dianion was discharged very slowly and an
orange suspension was obtained. To this orange suspension was added slowly one
equivalent of HMe2SiCl (1.18 g, 12.5 mmol) by syringe at 0°C. The resulting mixture was
stirred at RT for 10 h to give a yellow solution. All volatiles were removed under reduced
pressure and the residue was extracted with 3 x 100 mL of hexane. Filtration through
Celite was followed by removal of volatiles at reduced pressure to yield a yellow oil.
212
Compound 25 was obtained as a clear, colorless oil after purification by preparative GC.
The yield, determined by GC, was 52%.
1H
NMR (300 MHz, CDC13): 8 -0.30 (s, 6 H, CSiMe2 ), -0.29 (d, 3 J = 2.5 Hz, 6 H,
OSiMe2), 0.41 (s, 9 H, CMe3), 1.43 (s, 2 H, CH2Si), 4.16 (m, 3 J = 2.5 Hz,
1 H, SiH), 6.92 (m, 10 H, Ph).
13C NMR (75.4MHz, CDC13): 6 -5.2, -1.4, 16.7, 21.0, 26.2, 121.1, 125.4, 126.0,
127.6, 128.2, 130.3, 131.0, 141.5, 142.9, 150.0.
29 Si NMR (59.59 MHz, CDC13): 8 -3.85(CSi), 11.54(OSi).
IR (thin film, cm-l1 ): 3057(m), 3025(m), 2954(s), 2928(s,), 2896(m), 2124(s, SiH),
1624(m), 1598(m), 1494(s), 1442(s), 1253(m), 1230(s), 1002(m), 986(s).
Anal. Calcd. for C23H34 OSi2 : C, 72.18; H, 8.95. Found: C, 72.48; H, 8.95.
Preparation of Ph2 CHC(=O)CH2 SiMe 3 (26) (TW-IV.51)
Me3SiCI (13.5 g, 12.5 mmol) was added to a THF solution containing 12.5 mmol
of dianion 1 at 0 ° C by syringe. After the addition was complete, the mixture was stirred at
0 ° C for 30 minutes and then warmed to room temperature and stirred for 2 h. A solution
of saturated aqueous ammonium chloride was added to quench the reaction. The organic
layer was separated and the aqueous layer was extracted twice with Et2 O and the combined
organic layers were washed twice with water. The organic layer was dried over MgSO4
and all volatiles were removed using a rotary evaporator to leave 2.65 g of yellow oil
GLC analysis showed three products in the ratio 40:40:20. GCIMS showed three
molecular ion peaks at 354, 282, and 210. The mixture could not be separated by
213
distillation. A portion of this oil (1.5g) was chromatographed on alumina using first
hexane, then a 100:5 v / v hexane / ethyl acetate mixture as eluents to yield 19 (0.35g,
16%) and starting material l,l-diphenylacetone (0.55g, 42%). When this mixture of three
products was passed through a preparative GC column, 18 was isolated along with 19 and
1,1-diphenylacetone. By careful comparison of the NMR spectral data of the mixture with
the data obtained for pure samples of 18, 19 and 1,-diphenylacetone, the spectral data for
26 could be determined.
Spectral data for 26:
1H
NMR (300 MHz, CDC1 3): 8 0.11 (s, 9 H, SiMe 3 ), 2.31 (s, 2 H, CH 2), 5.09 (s, 1
H, CHPh 2 ), 7.19-7.32 (m, 10 H, Ph).
13 C
NMR (75.4MHz, CDC13): 6 -1.18 (q, J = 118.9 Hz, SiMe3), 37.9 (t, J = 123.0 Hz,
CH2), 65.1 (d, J = 127.0 Hz, CHPh2), 124.9-149.2 (m, Ph), 205.6(s, C=O).
Reaction of Ph2 C=C(CH3)OSiMe3
(17a) with LDA and quenching with
Me2HSiCI (PL).
A 100 mL round-bottomed Schlenk flask equipped with a magnetic stir bar and a
rubber septum was charged with 1.5 mL of diisopropylamine (9.0 mmol) in 40 mL THF.
One molar equivalent of nBuLi (3.6 mL of a 2.53 M solution, 9.0 mmol) was added at 0° C
and stirred for 10 min. A solution of 17a (2.53 g, 9.0 mmol) in 10 mL of THF was added
slowly to the stirred LDA/THF solution at 0°C. After stirring at 0° C for lh, a red solution
was obtained. To this red solution at 0°C was added one molar equivalent of Me2HSiCI
(0.85 g, 9.0 mmol). The resulting mixture was stirred at RT for 8 h to give a yellow
solution. All volatiles were removed under reduced pressure and the residue was extracted
with 3 x 100 mL of hexane. Filtration through Celite was followed by removal of volatiles
214
at reduced pressure to yield a yellow crude product. The product, which was isolated by
preparative GC, as determined by 1H NMR, was Ph2C=C(CH2SiMe3)OSiMe2H by
comparison of it to that of an authentic sample, 23.
Attempt hydrolysis of Ph2C=C(CH2SiMe3)OSiMe
3
(19) (TW-IV-73)
A solution of 20 mL of saturated aqueous ammonium chloride was added to a
solution of 19 (1 g, 2.8 mmol) in 50 mL of THF. The resulting mixture was stirred
vigorously at RT overnight. The organic layer was separated and the aqueous layer was
extracted twice with Et20 and the combined organic layers were washed twice with water.
The organic layer was dried over MgSO4 and all volatiles were removed using a rotary
evaporator to leave 0.9 g of a colorless oil, which was identified as a starting material
Ph2C=C(OSiMe3)CH2SiMe
1H
3,
19 by 1H NMR and
2 9 Si
NMR spectra.
NMR (300 MHz, CDC1 3 ): 6 -0.09 (s, 9 H, SiMe3), -0.01 (s, 9 H, OSiMe3), 1.68 (s,
2 H, CH2), 7.05 (m, 10 H, Ph).
2 9 Si
NMR (59.59 MHz, CDC1 3): 8 2.43 (CSi); 16.40 (OSi).
Preparation of Acetone Dianion [CH2 C(O)CH 2 ] 2 (2) (TW-II-28)
Acetone dianion [CH 2C(O)CH2] 2 - (2) was prepared according to a literature
procedure.4 A 100 mL round-bottomed Schlenk flask equipped with a magnetic stir bar
and a rubber septum was charged with 0.5 g (12.5 mmol) of potassium hydride and 50 mL
of Et2 O. Acetone (0.91 mL, 12.5 mmol) was added slowly to the flask by syringe.
Hydrogen gas evolution was observed. After stirring at room temperature for 20 min,
potassioacetone was obtained. To this white suspension at 0 ° C, one molar equivalent of nbutyllithium (7.8 mL of a 1.6 M solution) and one molar equivalent of
215
tetramethylethylenediamine
were added. The resulting yellow mixture was stirred at 0 ° C
under argon for 5-7 min, at which point it was ready for further reaction.
Attempted Reaction of Acetone Dianion [CH2 C(O)CH 2] 2 - (2) with Me2 SiCI2
(TW-I11145)
A yellow ether solution of the dianion 2 derived from 0.91 mL (12.5 mmol) of
acetone was added dropwise to a solution of 1.61 g (12.5 mmol) of Me2 SiC12 in 100 mL
of Et2 0 under N 2 at 0°C. The resulting mixture was stirred at 0 ° C for 2 h and then stirred
at room temperature for another 4 h. A yellow suspension was obtained. All volatiles
were removed at reduced pressure, and the residue was extracted with 3 x 100 mL of
hexane. Filtration through Celite was followed by removal of volatiles at reduced pressure
(250 C/20 mm Hg) to yield a yellow oily mixture, which could not be separated by
distillation and column chromatography. 29SiNMR spectrum of this yellow mixture
shows four major signals, which could not be assigned.
216
REFERENCES
1.
Chapter 1, this thesis
2.
Chiu, K. W.; Henderson, W.; Kemmitt, R. D. W.; Prouse, L. J. S.; Russell, D.
R. J. Chent Soc., Dalton Trans., 1988, 427.
3.
Trimitsis, G. B.; Hinkley, J. M.; Tenbrink, R.; Poli, M.; Gustafson, G.; Rop, J.
E. D. J. Am. Chem. Soc. 1977, 99, 4838.
4.
Hubbard, J. S.; Harris, T. M. J. Amn Chem Soc. 1980, 102, 2110.
5.
Birkofer, L.; Stuhl, O. In The Chemistry of Organic Silicon Compounds; Patai, S.;
Rappoport, Z., Ed.; Wiley: New York, 1989.
6.
Lukevics, E.; Pudova, O; Strukovich, R. "Molecular Structure of Organosilicon
Compounds", Ellis Horwood, Ltd: Chichester, 1989. p 175-208
7.
Allen, F. H.; Kennard, O.; Watson, D. G.; Brammer, L.; Orpen, A. G.; Taylor, R.
J. Chem Soc., Perkin Trans. 2 1987, 519.
8.
(a) Brook, A. G.; Macrae, D. M.; Limburg, W. W. J. AmntChent Soc. 1967,
89, 5493. (b) Brook, A. G. Acc. Chemn Res. 1974, 7, 77.
9.
Seyferth, D.; Robison, J. L.; Mercer, J. Organometallics 1990, 9, 2677.
10.
Launer, P. J. "Infrared Analysis of Organosilicon Compounds" in Silicon
Compounds Register and Review Petrarch Systems, 1987, 69.
11.
Rasmussen, J. K.; Hassner, A. J. Org. Chem. 1974, 39, 2558.
12.
House, H. O.; Czuba, L. J.; Gall, M.; Olmstead, H. D. J. Org. Chem 1969, 34,
2324.
13.
Corey, E. J.; Rucker, C. Tetrahedron Lett. 1984, 25, 4345.
14.
Brefort, J. -L; Corriu, R. J. P.; Guerin, C.; Henner, B. J. L.; Wong Chin Man,
W. W. C. Organometallics 1990, 9, 2080.
15.
Brook, A. G.; Chatterton, W. J.; Sawyer, J. F.; Hughes, D. W.; Vorspohl, K.
Organometallics 1987, 6, 1246.
217
16.
Rossmy, G.; Koerner, G. Makromol. Chem. 1964, 73, 85.
17.
Cragg, R. H.; Lane, R. D. J. Organomet. Chem. 1984, 270, 25.
18.
Gilman, H.; Cartledge, F. K.; Sim, S. -Y. J. Organomet. Chem. 1963, 1. 8.
19.
Hubbard, J. Tetrahedron 1988, 29, 3197.
20.
Ishikawa, M. Organometallic Syntheses 1986, 3, 512
21.
Sakurai, H.; Tominaga, K.; Watanabe, T.; Kumada, M. Tetrahedron Lett. 1966,
5493.
218
CHAPTER THREE
Reactions of Diphenylgermanium Dihalides with
the Ambident 1,1-Diphenylacetone Dianion
219
INTRODUCTION
2
In the previous two chapters, we reported that dianion 1, [CH2C(O)CR2] - (R =
Ph, H), is ambident in its reactions with metal dihalides. Dianions la and lb react
9.
OC
RC
2
1
'CH 2
a, R=Ph
b, R=H
with the oxophilic bis(cyclopentadienyl) dichlorides of zirconium and hafnium as C, O
dinucleophiles, giving 1,5-dimetalla-2,6-dioxa-3,7-dimethylenecyclooctanes,2, which
appear to dissociate in solution to form 2-metallaoxa-3-methylenecyclobutanes.
R
H2
R
C=C
R
H2C
Cp/
MO
Cp
2 M=Zr,Hf
R
220
Dianion lb reacts with cis-bis(triphenylphosphine)platinum dichloride as a C, Cdinucleophile, giving 3-metallacyclobutanone, 3.
Ph 3 P\
H
H
Ph3P -Pt
0O
\/
.C
H
In the reactions of dianion la with diorganosilicon dihalides, we observed a
marked difference in the regiochemistry of the reactions of R2SiC12and R2 SiF2 with the
1,1-diphenylacetone dianion. Compounds 4a-d were obtained from the reaction of
R2SiC12with la, while compounds 5a and 5b were isolated from the reaction of R2SiF2
with la. In both cases, dianion la reacts with diorganosilicon dihalides as a C, Odinucleophile.
Ph
C=C
--
Ph
Ph\
C=C/
O. SiC, H 2
H2 CsCH
R
2
Ph
HC Si
R
R2
4a R=R 2 =Me
4b R= R 2 =Et
/Ph
C
C
/ I
Ph
-
R% ,R
Rt ,,R2
O-Si 0
Ph
R
5a R=Et
5b R=Ph
4c R l = Me, R2 = H
4d R1= R 2 = Ph
The chemistry of germanium shows many similarities to that of silicon.1 It was
expected that acetone dianions also would react with diorganogermanium dihalides as C,O-
dinucleophiles.
221
We report here the results of the reactions of dianion la with Ph2GeC12 and
Ph2GeF2. In addition, we have found an improved method for the preparation of
Ph2GeF2.
222
RESULTS AND DISCUSSION
The reaction of the 1,1-diphenylacetone dianion,2 la, with
diphenyldichlorogermanewas carried out in a manner similar to the reaction of
[Ph2CC(O)CH2]2- with Ph2SiC12.In a typical experiment, a THF solution of dianion la
was added dropwise to one equivalent of Ph2GeCl2in THF at 0°C. During the addition,
the red color of the dianion was discharged slowly. Upon completion of the dianion
addition, the resulting mixture was stirred at room temperature overnight. A yellow
suspension was obtained. All volatiles were removed by evaporation under reduced
pressure, and the resulting residue was extracted with toluene. Filtration under nitrogen
through Celite left a pale yellow filtrate, which was evaporated under reduced pressure. A
colorless, air-stable solid was obtained in 45% yield after recrystallization from
dichloromethane/hexane at -23°C, mp: 242-244°C. The low yield obtained in this reaction
could be the result of 1,1-diphenylacetone dianion 1 attacking the solvent 3 due to a slow
reaction of the sterically hindered Ph2GeCI2with the l,l-diphenylacetone dianion.
Although a monomer, i.e., a 2-germaoxacyclobutane
(a germaoxetane), 6, could in
principle have been formed, the El mass spectrum of the solid product obtained in this
reaction showed as the highest mass peak one whose m / z, 872, was exactly twice the
molecular weight of 6, which indicated the presence of the "dimer", 7.
0
(C6H5 ) 2Ge
/C-C
H2
6
CPh 2
223
A determination of the molecular weight of 7 by vapor pressure osmometry (VPO)
in chloroform solution gave a value of 838, which is, within experimental error (< 10%),
the molecular weight of the eight-membered ring compound. This is consistent with the
data obtained from mass spectroscopy.
As in the case of the reactions of [Ph2CC(O)CH2]2- with Ph2 SiX2, there are two
possible eight-membered ring structures: A or B (Figure 1). Structure A has two
chemically different germanium atoms. Structure B has two chemically equivalent
germanium atoms.
Phx
0O
Ph
/Ph
Ph/
Ph
Ph.
Ph
Ge%0
OCG
O
H2Coe
e
Ph
Ph
2
Ph
Ph
Ge, CH2
,
O
CH2
.CH
Ge
Ph
Ph
Ph
A
Ph
Ph
B
Figure 1 Two possible structures for 7
1H
and
13C
NMR spectral data for 7 are given in Table 1. In the 1 H NMR
spectrum of 7 (Figure 2), the methylene CH2- group resonance appears as a singlet at
2.72 ppm. The
13 C NMR spectral data are
consistent with the results from the 1 H NMR
spectrum (Figure 3), exhibiting a triplet for the CH2- group at 26.8 ppm with a coupling
constant J =127 Hz. However, as with the Si analogs, the 1H and
not allow conclusive identification of the structure of 7.
13C
NMR spectra did
224
-c\
em
IC.
--
-. 0A
V
Lo
O"
II
U
Q
vA
e
ZCD
Ln
090"
UX
z
-o
-t-
-rC
225
x3:
a.
a
0
Etu
o
oSvo
N
----LC-P·
-I
_I _
- Y,
.
0
M
A
1 0
Q
A
n
I.-,
Q
QI
0
0
L
-.,
a
e
0
:-0
_
_
_
M"i
-
e0
--z,
z
Lo
_.
n~
- 0
0
-0
a
226
Table 1. NMR spectral Data for 7
NMR
6
Mult
J (Hz)
Area
Assignment
1H
2.72
s
-
4
CH2
6.77-7.38
m
-
40
Ph
26.8
t
127
-
CH2
121.:3
s
-
-
125.0-141.5
m
-
-
Ph
t
(2 J)
-
CH2C=CPh2
13 C
148.4
5
CH2C=CPh
2
The mass spectrum of 7 is of interest. Selected m / z data are given in Table 2. A
known four-membered ring germaoxetane is known to decompose to [2 + 2] products in
mass spectrometry experiments (electron impact) by two routes (Scheme 1).4 In the mass
spectrum of 7, besides the molecular ion peaks, a [8] -- [4] -- [2 + 2] decomposition of
the eight-membered ring was observed. For structure A, one germanium atom is bonded
to two oxygen atoms which basically makes dissociation of two four-membered
monomeric ring compounds impossible. On the other hand, structure B, similar to that of
the (115 -C5 H 5)2Zr analog, 2, could decompose to the four-membered ring germaoxetane as
shown in Scheme 2, with further decomposition to the germanone and 1,1diphenylallene.
Table 2. Selected mass spectrometry data for 7
compound
7 (C54H44Ge202)
Calcd. (7 4 Ge)
872
m/z (fragment: relative intensity)
872 (M + , 30)
436 (0.5 M + , 100)
244 (Ph2Ge=O, 66)
192 (Ph2C=C=CH 2, 20)
227
Scheme
1
a
Mes2Ge -, - CR 2
I
Mes 2Ge
CR2 + Ph(R')C=O
Mes 2Ge-
O + Ph(R')C--CR
:_
O-:- CR'Ph
O--CRPh
b=
2
Scheme 2
Ph
2 Ph2Ge /
Ph
C=
CPh 2
H2
B
Ph2 Ge-O
+ Ph2C-C--- CH 2
In order to establish the structural identity of 7, a single crystal X-ray diffraction
study was performed by Professor Arnold Rheingold at the University of Delaware,
Newark, DE.
Single crystals of X-ray quality were obtained by dissolving 7 in a minimum
amount of methylene chloride, followed by the addition of two equivalents of hexane and
storing the solution at room temperature for two days. Figure 4 shows an ORTEP plot of
the molecule. In contrast to the product of the analogous reaction of the [Ph2CC(O)CH2 ]2 /Ph2 SiCI2, compound 7 possesses a structure of type B. The eight-membered ring of 7 is
crown-shaped. This can readily be seen in the side view, C atom only plot as shown in
Figure 5. Selected bond distances and bond angles are given in Table 3 and Table 4.
228
The Ge-O and Ge-C bond distances (1.778(9); 1.791(10) and 1.962(13); 1.955(13)
A ) are
normal and are in the ranges (1.73-1.79 A5and 1.90-1.98 A6) for tetrahedral germanium.
Table 3. Selected intramolecular bond distances for 7
Atom
Atom
Distance
Atom
Atom
Distance
Ge(l)
Ge(l)
0(6)
1.778(9)
Ge(2)
0(7)
1.791(10)
C(5)
1.962(13)
Ge(2)
C(1)
1.955(13)
C(1)
C(2)
1.524(20)
C(4)
C(5)
1.484(20)
0(6)
C(2)
0(7)
C(4)
1.363(18)
C(2)
C(3)
1.368(19)
1.341(23)
C(4)
C(8)
1.329(22)
Table 4. Selected intramolecular bond angles for 7
Angle
111.4(5)
Atom
Atom
Atom
Angle
Ge(l)
C(5)
C(4)
111.7(10)
114.6(12)
Ge(2)
0(7)
C(4)
126.4(8)
109.5(5)
Ge(2)
C(1)
C(2)
Ge(l)
0(6)
C(2)
C(3)
113.1(13)
125.6(14)
111.0(9)
129.9(9)
C(3)
C(2)
0(6)
121.3(14)
C(4)
C(8)
125.6(14)
0(7)
C(4)
C(8)
119.8(13)
C(3)
C(66)
125.8(13)
C(76)
C(8)
C(86)
114.4(11)
Atom
Atom
Atom
C(5)
Ge(l)
C(5)
C(4)
C(1)
Ge(2)
C(1)
C(1)
C(2)
C(2)
0(6)
0(7)
0(7)
0(6)
C(5)
C(56)
229
0N
f.
r
Is
'S
0*
41
o
a;
230
ZU')
u
-
4
A
AN
11
1--
02
Q
*eL
II
e4
1._
Qa
-
0
)
Im
tA
1
o
SW
CO
231
In the reaction of [Ph2CC(O)CH2] 2 - with Ph2SiCI2, we have suggested that 2silaoxetane was not the intermediate, resulting in a compound of structure type A (chapter
2). In the reaction of [Ph2CC(O)CH2]
2 - with
Ph2GeCI2, we suggest that the 2-
germaoxetane is the first intermediate, probably due to the more reactive Ge-Cl bond, and
that this four-membered ring intermediate undergoes ring-opening cyclodimerization to give
the observed 7 as shown in Scheme 3.
Scheme 3
2M
+
PhC'-
Ph2GeCI2
-
Ph[
CPh2
+ 2MCI
'CH 2
Ph
Ph
Ph / Ge,
Ph
Ph
Ph
The proposed mechanism seems reasonable in terms of known
chemistry. Unlike the silicon analogs, cyclodimerizations of 2-germaoxetanes have been
well documented in the literature.9- 12 Castel and Satg6 reported that insertion of Ph2Ge
into an oxirane ring led to a 2-germaoxetane which dimerized to give a digermadioxocane
(eq. 1).10
232
Ph2GeoNEt
3 + H 2 C-- H 2
hv
Phe
\
CH2
35°C
0
C
2
IH2~~
Ph.
(1)
Ph
O'Ge
CH2
1/2 H 2 C
CH
2
H2C-G O0
Ge
Ph/
'Ph
In further experiments, dianion 1 also was allowed to react with Ph 2 GeF2 .
Surprisingly, Ph 2 GeF2 has been reported in only two papers since 1930.13, 14 Kraus and
Brown reported obtaining Ph 2 GeF2 by hydrolyzing diphenyldichlorogermane and treating
the resulting diphenylgermanium oxide with concentrated hydrofluoric acid. 13 No yield
was reported. Attempts were made to repeat Kraus' work. In several tries Ph2 GeF2 was
obtained in very low yield along with diphenylgermanium oxide. This would seem to
suggest that the Ph 2 GeF2 formed was hydrolyzed again under the experimental conditions.
In order to prepare Ph2GeF2 in high yield, we turned to halogen exchange
reactions. Silver fluoride had been used as a fluoride source in such reaction by Anderson
who classified triorganogermanium halides according to their reactivity towards silver
halides:
-Ge-I
/
> -Ge-Br > -Ge-C1 > -Ge-F
/
/
/
233
In this series any germanium halide, through a reaction with the proper silver halide, may
be transformed into the halide following it, but cannot be transformed into a halide which
precedes it.1 5
In our synthesis (eq. 2), a solution of diphenyldichlorogermane in 10 mL of
CH3CN was added slowly to an excess of silver fluoride in CH3CN at room temperature.
Ph2GeCl2 + excess AgF
CH3 CN
-
PhGeF 2 + 2 AgCl
(2)
A white precipitate formed immediately. Suitable workup gave diphenyldifluorogermane
as a colorless solid in 87% yield after recrystallization from hexane, mp 47-48 0 C.
(Diphenyldifluorogermane prepared by reaction of diphenylgermanium oxide with
concentrated hydrofluoric acid was reported as a colorless liquid with a boiling point of
100°C at a pressure of 0.007 mm Hg. 13)
The reaction of the [CH2C(O)CPh2]2 - dianion with diphenyldifluorogermanewas
carried out using the same conditions as were used in the reaction of [CH2 C(O)CPh2]2with Ph 2 GeCI2 (eq. 3). After fractional crystallization from dichloromethane/hexane, it
Ph
Ph
.Ge.
O
ei: (e
PhC
/Ph
CH2
Ph2GeF2
CH2
Ph\
Ph/
(
H2 CGe%
Ph Ph
was apparent that the white crystals isolated in 15% yield from this reaction were the same
product as 7 since their melting points was exactly the same, 242-2440 C. The MS
spectrum showed the same fragmentation pattern as 7. Similar to the reaction of
234
[CH2 C(O)CPh21 2 - with Ph2GeCl2, the low yield of this reaction could be due to
competitive attack of the 1,-diphenylacetone
dianion 1 on the THF solvent. Attempts to
analyze the residue left from the recrystallization of 7 have to date been unsuccessful.
Attempts were made to react the [CH2 C(O)CPh2] 2 - dianion with
dialkyldichlorogermanes (dimethyldichlorogermane, diethyldichlorogermane and di-nbutyldichlorogermane).
It was apparent that some reaction had occurred. However, pure
products could not be isolated.
235
EXPERIMENTAL SECTION
General Comments.
All reactions were performed under an inert atmosphere using standard Schlenk
techniques. All solvents were distilled under nitrogen from the appropriate drying agents.
Chlorogermanes were purchased from Gelest and distilled from magnesium chips before
use. n-Butyllithium in hexane was purchased from Aldrich and titrated for RLi content by
Gilman double-titration method.16 l,l-Diphenylacetone was purchased from Aldrich and
used without further purification. Potassium hydride was purified by washing it with a
THF solution of lithium aluminum hydride (approximately 4 mmol lithium aluminum
hydride in 10 mL THF). 1 7
1H
NMR spectra were obtained with a Varian XL-300 NMR spectrometer and
listed in parts per million downfield from tetramethylsilane. 13CNMR spectra, both proton
coupled and decoupled, were obtained using a Varian XL-300 NMR spectrometer
operating at 75.4 MHz in CDC13 The 19 F {1H) NMR spectrum was obtained using a
Varian XL-300 NMR spectrometer operating at 282.4 MHz in CDC13, using CFC13 as the
external standard at 0.00 ppm.
Electron impact mass spectra(MS) were obtained using a Finnigan-3200 mass
spectrometer operating at 70 eV. Infrared spectra (KBr) were obtained using a PerkinElmer 1600 Fourier Transform Infrared spectrophotometer. Melting points of analytically
pure products were determined in air using a Biichi melting point apparatus. Elemental
analyses were performed by the Scandinavian Microanalytical Laboratory, Herlev,
Denmark
236
Vapor Pressure Osmometry
Molecular weight determinations were carried out using a Wescan Model 233
Molecular Weight Apparatus (vapor pressure osmometry). Vapor pressure osmometry
operates on the principle that the vapor pressure of a solution is lower than that of the pure
solvent at the same temperature, but by raising the temperature of the solution its vapor
pressure can be raised to match that of the solvent. Equation 4 is derived from Raoult's
law and used for calculation of molecular weight.
KxC
(4)
m
where
A V = a voltage change
C = concentration
m = molecular weight
K = calibration factor
Sucrose octaacetate was used as a standard and all measurements were carried out
in chloroform. The calibration factor K was determined by measuring A V and C for the
known molecular weight of sucrose octaacetate (Mol. Wt. 678.6). By reversing the
procedure, unknown molecular weights are determined using that factor K.
Three different concentration of sucrose octaacetate solution were prepared. The
results for determination of calibration factor K are given in Table 5. The Wescan Model
233 Molecular Weight Apparatus were operated in the following condition:
Current: 50 microamperes.
Operating temperature: 40°C.
Average solvent reading: 2.0 microvolts.
237
Table 5. Determination of calibration factor K
Concentration
(mg/mL)
0.7
3.0
6.2
Reading
(microvolts)
6.59
(solution-solvent)
4.59
21.40
19.40
40.69
38.69
AV
AV/C
6.56
6.45
6.24
The determined values of AV/C are plotted versus concentration and a best fit
straight line is extrapolated to zero concentration. This extrapolated value of AV/C is used
to calculate the calibration factor K in equation 4 by multiplying it by the molecular weight
of the sucrose octaacetate. The extrapolates value is 6.62. The calibration factor K is
678.6 x 6.62 = 4492. The plot is show in Figure 6.
7.0'
I
6.8
M
y = 6.6222 - 0.0592x R = 0.98
6.6
U 6.4
*
< 6.26.0
5.8
-
5.6-
-
)
-
II
1
-
'
I
2
·
·
·
3
4
·
·
5
u
·
.
I
6
C
Figure 6. Calibration factor K for VPO
7
A V/C
238
X-ray Crystallography
Structure of 7
The structure of 7 was solved by Professor Arnold Rheingold at the University of
Delaware, Newark, DE.
The colorless crystals of 7 were obtained by dissolving it in methylene chloride and
allowing the solution to evaporate slowly. A colorless block was mounted on a glass fiber
and found to possess 2 / m Laue symmetry. Data were collected at 296K using MoKa
radiation on a Siemens P4 diffractometer. All specimens studied diffracted weakly and
somewhat broadly; as a consequence data were not available beyond 2 0 = 42° . No
correction for absorption was required; azimuthal scans showed < 10% variation. The
structure was solved by direct methods and refined by full-matrix least-squares techniques.
The limited available data required the use of rigid-body constraints on the phenyl rings and
prevented anisotropic refinement of their carbon atoms. All other non-hydrogen atoms
were refined anisotropically. Hydrogen atoms were idealized. Final R = 0.0614 and Rw =
0.0769 for 1996 observed reflections (F > 5.0(F)) and 187 variables. A summary of data
collection details and crystal data appear in Table 6-11
239
Table 6. Crystal data for 7.
Empirical formula
Color; Habit
C54H44Ge202
Colorless block
Crystal Size (mm)
0.2 x 0.2 x 0.3
Crystal System
monoclinic
Space group
P21 /n
Unit Cell Dimensions
a.= 15.044(8) A
b= 17.048(7) A
c= 17.191(8) A
Volume
4402(3) A3
z
4
Formula weight
870.1
Density(calc.)
1.310 g/cm3
Absorption Coefficient
0.403 mm
F(000)
1792
'1
240
Table 7. Data collection for 7
Radiation
Temperature (K)
Siemens P4
MoKa (1= 0.71073 A)
296
Monochromator
Highly oriented graphite crystal
20 Range
4.0 to 41.00
Diffractometer Used
Scan Type
Scan Speed
Variable; 5.33 to 19.530°/min. in o
Scan Range (o)
1.000
Background Measurement
Stationary crystal and stationary counter
at beginning and end of scan, each for
50.0% of total scan time
Standard Reflections
3 measured every 197 reflections
Index Ranges
-14< h < 13,0<k< 16
0<1<16
Reflections collected
4424
Independent Reflections
Observed Reflections
4252 (Rint = 2.54%)
1996 (F > 5.0a(F))
Absorption Correction
N/A
241
Table 8 Structure solution and refinement for 7
System Used
Siemens SHELXTL PLUS (PC
Version)
Solution
Refinement Method
Direct Methods
Quantity Minimized
Zw(Fo-Fc)2
Absolute Structure
N/A
Extinction Correction
N/A
Hydrogen Atoms
Riding model, fixed isotropic U
Weighting Scheme
w-1 = a2 (F) + 0.0010F2
Number of parameters Refined
187
Final R Indices (obs. data)
R Indices (all data)
R = 6.14 %, wR 7.69 %
R = 11.03 %, wR 8.40 %
Goodness-of-Fit
1.60
Largest and Mean D/s
0.011, 0.002
Data-to-parameter Ratio
10.7:1
Largest Difference Peak
0.61 eA -3
Largest Difference Hole
-0.46 eA- 3
Full-Matrix Least-Squares
242
Table 9
Atomic coordinates (x104) and equivalent isotropic displacement
coefficients (A2 x103) for 7
U(eq)
y
z
2510(1)
2388(1)
2013.2(9)
52(1)*
4791(1)
3660(9)
2525(1)
2814(8)
3162.5(8)
3592(8)
55(1)*
53(6)*
C(2)
C(3)
C(4)
3237(10)
2777(9)
4312(10)
2111(9)
1752(8))
2221(8)
3610(10)
4254(9)
1581(9)
56(7)*
55(6)*
49(7)*
C(5)
0(6)
3589(9)
2764(6)
2813(8)
1850(5)
1580(7)
2884(5)
53(6)*
58(4)*
0(7)
C(8)
4582(6)
4678(9)
1948(5)
1938(8)
2301(6)
953(9)
57(4)*
52(6)*
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
C(31)
C(32)
C(33)
C(34)
C(35)
C(36)
C(41)
C(42)
C(43)
C(44)
1058(7)
505**
612**
1271
1824
1717
2377(5)
1988
1191
782
1171
1969
5205(6)
5681
6408
6659
6182
5455
5266(6)
5732
6392
6587
3044(5)
3647
4406
4563
3960
3201
834(6)
236
371
1105
1703
1568
4190(7)
4847
4760
4015
3357
3444
994(7)
449
701
1498
2810(5)
3046
2763
2244
2008
2261
1375(5)
920
488
512
968
1399
3134(5)
2913
2449
2208
2429
2892
3707(6)
4176
4721
4795
66(5)
88(6)
88(6)
95(6)
71(5)
48(4)
76(5)
107(7)
119(7)
159(9)
103(6)
56(4)
106(7)
124(7)
123(7)
141(8)
108(7)
62(5)
111(7)
147(9)
122(7)
131(8)
C(45)
6122
2044
4326
108(7)
C(46)
C(51)
C(52)
C(53)
C(54)
C(55)
C(56)
C(61)
C(62)
C(63)
5461
1805(7)
1226
987
1326
1905
2145
2768(6)
3129
3868
1792
700(6)
66
-186
195
829
1081
2684(6)
2927
2541
3781
3606(5)
3668
4400
5070
5008
4276
5401(7)
6125
6468
56(4)
76(5)
96(6)
88(6)
93(6)
86(6)
65(5)
103(6)
117(7)
113(7)
C(64)
4246
1911
6086
94(6)
C(65)
3885
1668
5362
69(5)
C(66)
3146
2054
5019
61(5)
C(71)
C(72)
4839(6)
4544
2854(6)
3164
-173(6)
-892
93(6)
85(6)
Atom
x
Ge(l)
Ge(2)
C(1)
243
C(73)
C(74)
C(75)
3773
3299
3595
2871
2267
1956
-1276
-941
-222
89(6)
97(6)
78(5)
C(76)
4365
2250
162
62(5)
C(81)
C(82)
C(83)
5889(8)
6524
6672
1088(6)
495
142
1606(5)
1564
850
92(6)
113(7)
113(7)
C(84)
C(85)
C(86)
6184
5549
5402
382
975
1328
178
221
935
139(8)
111(7)
67(5)
* Equivalent isotropic U defined as one third of the trace of the orthogonalized Uii tensor
**The limited available data required the use of rigid-body constraints on the phenyl rings
and prevented anisotropic refinement of their carbon atoms.
244
Table 10
Intramolecular bond distances (A) for 7, involving the non-hydrogen
atoms.
Atom
Atom
Distance
Atom
Atom
Distance
Ge(l)
Ge(l)
C(5)
1.962(13)
C(16)
C(1)
Ge(2)
C(1)
C(36)
C(2)
1.906(9)
1.955(13)
1.928(12)
0(6)
C(26)
Ge(2)
Ge(1)
Ge(1)
Ge(2)
Ge(2)
0(6)
1.524(20)
1.368(19)
1.491(19)
1.363(18)
1.513(18)
1.395
C(2)
C(2)
C(3)
C(4)
C(8)
C(3)
C(56)
C(5)
1.778(9)
1.907(10)
1.791(10)
1.896(11)
1.341(23)
1.491(17)
1.395
C(13)
C(15)
C(66)
0(7)
C(14)
C(76)
C(12)
C(13)
C(15)
C(21)
C(22)
C(22)
C(25)
C(31)
C(32)
C(34)
C(41)
C(42)
C(44)
C(23)
C(26)
C(32)
C(33)
C(35)
C(42)
C(43)
C(45)
C(52)
C(11)
C(12)
C(51)
C(52)
C(54)
C(61)
C(62)
C(64)
C(71)
C(72)
C(74)
C(81)
C(82)
C(84)
C(53)
C(55)
C(62)
C(63)
C(65)
C(72)
C(73)
C(75)
C(82)
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
C(83)
1.395
1.395
1.395
1.395
C(85)
1.396
C(3)
C(4)
C(4)
C(8)
C(11)
C(21)
C(23)
C(25)
C(31)
C(33)
C(35)
C(41)
C(43)
C(45)
C(51)
C(53)
C(55)
0(7)
C(46)
C(8)
C(86)
C(16)
C(14)
C(16)
C(26)
C(24)
C(26)
C(36)
C(34)
C(36)
C(46)
C(44)
C(46)
C(56)
C(54)
C(56)
C(61)
C(63)
C(65)
C(71)
C(73)
C(66)
C(64)
C(66)
C(75)
C(76)
C(86)
C(81)
C(83)
C(85)
C(76)
C(74)
C(84)
C(86)
1.484(20)
1.329(22)
1.507(18)
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
1.395
245
Table 11 Intramolecular bond angles () for 7, involving the non-hydrogen atoms.
Atom
Atom
Atom
Angle
Atom
Atom
Atom
Angle
Ge(1)
Ge(1)
Ge(1)
C(16)
C(26)
C(26)
C(36)
C(46)
C(46)
111.6(5)
C(S)
Ge(1)
0(6)
0(6)
0(6)
Ge(1)
Ge(1)
C(16)
C(26)
111.4(5)
105.9(4)
C(5)
C(5)
98.9(4)
C(16)
C(1)
0(7)
109.5(5)
Ge(2)
Ge(2)
Ge(2)
Ge(2)
Ge(2)
Ge(2)
C(1)
C(1)
C(2)
C(56)
C(S)
Ge(1)
C(4)
0(7)
C(2)
C(2)
C(3)
C(4)
C(4)
Ge(1)
0(6)
Ge(2)
C(4)
C(12)
C(12)
C(14)
0(7)
126.4(8)
126.9(13)
C(4)
C(8)
C(76)
120.0
C(
120.0
C(13)
120.0
Ge(1)
120.1(3)
C(
120.0
120.0
120.0
120.2(3)
120.0
120.0
120.0
118.9(3)
120.0
120.0
120.0
120.7(3)
120.0
120.0
120.0
C(21)
C(23)
Ge(1)
C(21)
C(31)
C(33)
Ge(2)
C(31)
C(41)
C(43)
Ge(2)
C(41)
C(51)
C(53)
C(3)
C(51)
C(61)
C(63)
C(3)
C(61)
C(8)
C(12)
C(14)
C(16)
C(16)
C(22)
C(24)
C(26)
C(26)
C(32)
C(34)
C(36)
C(36)
C(42)
C(44)
C(46)
C(46)
C(52)
C(54)
C(56)
C(56)
C(62)
C(64)
C(66)
C(66)
C(72)
C(74)
C(76)
C(76)
C(82)
C(84)
C(86)
C(86)
0(7)
0(7)
C(36)
C(46)
C(2)
108.5(4)
99.6(4)
C(1)
C(1)
C(36)
111.0(9)
C91)
C(2)
0(6)
C(3)
C(3)
C(56)
C(66)
C(8)
C(4)
C(4)
C(86)
C(16)
C(14)
C(16)
C(15)
C(26)
C(26)
C(26)
C(25)
C(36)
C(34)
C(36)
C(35)
C(46)
C(44)
C(46)
C(45)
C(56)
C(54)
C(56)
C(55)
C(66)
C(64)
C(66)
C(65)
C(76)
C(74)
C(76)
C(75)
C(86)
C(84)
C(86)
C(85)
113.1(13)
125.8(13)
C(3)
C(2)
C(5)
C(S)
C(8)
C( 1)
C(13)
C(15)
Ge(1)
C(16)
C(22)
C(22)
C(24)
C(21)
C(23)
C(25)
Ge(1)
C(26)
C(32)
C(32)
C(34)
Ge(2)
C(42)
C(42)
C(44)
Ge(2)
C(52)
C(52)
C(54)
C(3)
C(62)
C(62)
C(64)
C(31)
C(3)
C(66)
C(72)
C(72)
C(74)
C(71)
C(73)
C(8)
C(82)
C(33)
C(35)
C(36)
C(41)
C(43)
C(45)
C(46)
C(51)
C(53)
C(55)
C(56)
C(61)
C(63)
C(65)
C(75)
C(76)
C(84)
C(81)
C(83)
C(85)
C(8)
C(86)
C(82)
116.8(11)
125.6(14)
111.7(10)
117.1(7)
120.0
120.0
120.0
117.4(7)
120.0
120.0
120.0
120.7(6)
120.0
120.0
120.0
117.8(7)
1)
1)
C(71)
C(73)
C(8)
C(71)
C(81)
C(83)
C(8)
C(81)
Ge(2)
113.4(5)
114.7(4)
111.0(5)
113.6(5)
0(6)
113.9(4)
125.6(14)
121.3(14)
C(66)
117.4(13)
0(76)
114.6(12)
C(8)
C(2)
C(76)
C(86)
C(13)
C(15)
119.8(13)
C(3)
129.9(9)
118.7(12)
114.4(11)
C(15)
C(23)
C(25)
120.0
120.0
119.8(3)
120.0
120.0
120.0
C(21)
119.8(3)
C(25)
C(33)
C(35)
120.0
120.0
120.0
C(31)
121.1(3)
C(35)
C(43)
C(45)
120.0
120.0
120.0
C(41)
119.2(3)
C(45)
120.0
120.0
120.0
C( 1)
C(53)
C(55)
C(51)
C(55)
C(63)
C(65)
C(61)
C(65)
C(73)
C(75)
C(71)
C(75)
C(83)
C985)
C(81)
C(85)
122.9(7)
120.0
120.0
120.0
122.6(7)
120.0
120.0
120.0
119.3(6)
120.0
120.0
120.0
122.2(7)
120.0
246
Preparation of Diphenyldifluorogermane
(TW-V-18, 19).
A 100 mL round-bottomed Schlenk flask wrapped with aluminum foil and
equipped with a magnetic stir bar and a rubber septum was charged with 1.3 g (10.2 mmol,
50% excess) of silver fluoride and 30 mL of CH3CN. A solution of
diphenyldichlorogermane (1.0 g, 3.36 mmol) in 10 mL of CH3CN was added slowly to
the flask by cannula at room temperature. After stirring at room temperature overnight, a
cloudy suspension was obtained. CH3CN was removed by evaporation at reduced
pressure, and the resulting residue was extracted with hexane (3 x 100 mL). Filtration
under nitrogen left a colorless solution. The filtrate was concentrated to about 30 mL under
reduced pressure and stored at -23°C overnight. Diphenyldifluorogermane was obtained as
a colorless solid, 0.77 g (87%), after recrystallization from hexane, mp 47-48°C.
1H
19 F
NMR (300 MHz, CDC13): 8 7.23-7.75 (m)
NMR (300 MHz, CDC13): 8-167.7
GC/MS: (7 4Ge); Calcd for C12H1oGeF2:266; Found: 266 (M+), 247 (M+ - F),
228 (M+ - 2F), 189 (M+ - Ph), 154, 128, 93, 77 (Ph). 51.
Anal.: Calcd for C12H1oGeF2:C, 54.43; H, 3.81. Found: C, 54.55; H, 3.92.
Preparation of 1,1-Diphenylacetone
Dianion [Ph 2 CC(O)CH 2 ] 2 - (1) (TW-I-
72, 11-6)
1,1-Diphenylacetone dianion, [Ph2CC(O)CH2]2- (1), was prepared according to a
literature procedure. 5 A 100 mL round-bottomed Schlenk flask equipped with a magnetic
stir bar and a rubber septum was charged with 0.25 g (6.25 mmol) of potassium hydride
and 50 mL of THF. A solution of 1,l-diphenylacetone (1.31 g, 6.25 mmol) in 10 mL of
247
THF was added slowly to the flask by cannula. Hydrogen gas evolution was observed.
After stirring at room temperature for 15-20 minutes, a clear orange solution was obtained.
To this orange solution at 0°C, one molar equivalent of n-butyllithium was added (3.9 mL
of a 1.6 M solution). The resulting red mixture was stirred at 0C under argon for 5-7
min., at which point it was ready for further reaction.
Preparation of 1,1,5,5-Tetraphenyl-3,7-bis(diphenylmethylene)-1,5digerma-2,6-dioxacyclooctane
(7) (TW-V-5, 26, 27).
A 250 mL round-bottomed Schlenk flask equipped with a magnetic stir bar and a
rubber septum was charged with 1.86 g (6.25 mmol) of Ph2 GeCI2 and 100 mL of THF.
To this solution at 0° C was added slowly by cannula 6.25 mmol of 1,1-diphenylacetone
dianion in 50 mL of THF (eq. 1). The resulting mixture was stirred at room temperature
overnight. A yellow suspension was obtained. All volatiles were removed by evaporation
under reduced pressure, and the resulting residue was extracted with toluene (3 x 80 mL).
Filtration under nitrogen through Celite left a pale yellow filtrate which was evaporated
under reduced pressure. Compound 7 was obtained as a colorless, air-stable solid, 2.5 g
(45%), after recrystallization from dichloromethane and hexane at -23 0 C, mp 242-244 0 C.
Single crystals of X-ray quality were obtained by dissolving 7 in a minimum amount of
methylene chloride, adding two volume equivalents of hexane and letting the solution stand
at room temperature for two days.
1H NMR (300 MHz, CDC13 ): 8 2.72 (s, 4 H, CH2), 6.77-7.38 (m, 40 H, Ph).
13C NMR (75.4MHz, CDC1 3 ): 8 26.8 (t, J = 127 Hz CH 2 ), 121.3 (s, CH 2 C=CPh 2 ),
125.0-141.5 (m, Ph), 148.4 (t, 2J = 5 Hz, CH2C=CPh2).
248
MS (EI, 74 Ge); Calcd for C54H4402Ge2:872; Found: m/z (fragment, relative intensity):
872 (M+ , 26). 680 (M+ - Ph2 C--CCH2 , 7), 664 (M+ - Ph2 C-C(O)CH 2, 1),
436 (0.5 M+ , 100), 394 (30), 305 (25), 244 (Ph2Ge=O, 16), 227 (21), 192
(Ph2C=C=CH2, 9), 166 (Ph2C, 24), 151 (29).
IR (KBr, cm-1 ): 3050(m), 3022(m), 1599(s), 1492(m), 1441(m), 1431(w),
1401(w), 1319(w), 1239(s), 1182(m), 1097(s), 1071(w), 965(s), 899(w),
767(s).
Anal.: Calcd for C54H4402Ge2: C, 74.54; H, 5.10. Found: C, 74.27; H, 5.12.
Mol. wt.: (VPO, CHCI3) Calcd for C54H4402Ge2: 870. Found: 838
Solution with three different concentrations of 7 were prepared and A V values
were determined. The data was given in Table 12. A plot of A V/C versus C (Figure 7)
was prepared and the zero concentration intercept was used to calculate the molecular
weight. The extrapolated value is 5.36. The molecular weight then was calculated to be
4492/5.36 = 838 g/mol.
Table 12. Determination of molecular weight of 7
Concentration
Reading
AV
(mg/mL)
(microvolts)
(solution-solvent)
0.8
6.2
4.2
5.3
2.9
17.1
15.1
5.2
5.6
30.0
28.0
5.0
AV/C
249
5.4
5.3
Q
5.2
<
5.1
N
AV/C
5.0
4.9
0
1
2
3
4
5
6
C
Figure 7. VPO data for [Ph2 GeCH2(=CPh2)02, 7
Reaction of 1,1-Diphenylacetone
Diphenyldifluorogermane
Dianion [Ph2CC(O)CH2] 2 - (1) with
(TW-V-23, 24).
A THF solution containing 6.25 mmol of dianion 1 was added dropwise to one
molar equivalent of Ph2GeF2 (1.65 g, 6.25 mmol) in 100 ml of THF at 0°C (eq. 2). The
red color of the dianion was discharged very slowly. Upon completion of the dianion
addition, the resulting mixture was stirred at room temperature overnight. A red
suspension was obtained. All volatiles were removed by evaporation under reduced
pressure, and the resulting residue was extracted with toluene (3 x 80 mL). Filtration
under nitrogen through Celite left a pale yellow filtrate. The filtrate was evaporated under
reduced pressure. Compound 7 was obtained as colorless crystals in 15% yield after three
recrystallization from dichloromethane and hexane at -230 C. The identity of the product was
confirmed by comparison of the 1 H NMR spectrum, the 13 C NMR spectrum, MS
spectrum and mp with those of the product of the [Ph2CCOCH2]2 - /Ph2GeCI2reaction. A
mixed mp of the products for the [Ph2CCOCH2]2 - /Ph2GeCI2 reaction and the
250
[Ph2 CCOCH2] 2 /Ph2GeF2 reaction was identical to the mp of the product of the
[Ph2 CCOCH 2 ] 2- /Ph2 GeC12 reaction (242-244 0 C).
251
REFERENCES
1.
Lesbre, M.; Mazerolles, P.; Satg6, J. "The Organic Compounds of Germnnanium"
Wiley; New York, 1971, p.2 .
2.
Trimitsis, G. B.; Hinkley, J. M.; Tenbrink, R.; Poli, M.; Gustafson, G.; Rop, J.
E. D. J. Am. Chemn Soc. 1977, 99, 4838.
3.
Hubbard, J. S.; Harris, T. M. J. Am. Chem. Soc. 1980, 102, 2110.
4.
Lazraq, M.; Couret, C.; Escudid, J.; Satg6, J.; Driger, M. Organometallics 1991,
10, 1771.
5.
Ross, L.; Driger, M. Z. Naturforsch. 1984, 39B, 868.
6.
Driger, M.; Ross, L.; Simon, D. Rev. Silicon, Germanium, Tin and Lead Compd.
1983, 7, 299.
7.
Brook, A. G.; Chatterton, W. J.; Sawyer, J. F.; Hughes, D. W.; Vorspohl, K.
Organometallics 1987, 6, 1246.
8.
Wiberg, N.; Kim, C. K. Chemn Ber. 1986, 119, 2966, 2980.
9.
Satge, J. Pure AppL Chemn 1984, 56, 137.
10.
Castel, A.; Riviere, P.; Satgd, J.; Cazes, A.; C. R. Acad Sci. Paris 1978,
287 (C), 205.
11.
Barrau, J.; Bouchaut, M.; Lavayssiere, H.; Dousse, G.; Satg6, J. J. Organomet.
Chem. 1983,243, 282.
12.
Barrau, J.; Massol, M.; Mesnard, D.; Satgd, J. Recl. Trav. Chimn Pays-Bas 1973,
92, 321.
13.
Kraus, C. A.; Brown, C. L. J. Anm Chemn Soc. 1930,52, 3690
14.
Metlesics, W.; Zeiss, H, J. Am. Chemn Soc. 1960, 82, 3324
15.
(a)
Anderson, H. H. J. Amn Chemn Soc. 1951, 73, 5440.
(b)
Anderson, H. H. J. Amn Chemn Soc. 1956, 78, 1692.
252
16.
Gilman, H.; Cartledge, F. K.; Sim, S. -Y. J. Organomet. Chem. 1963, 1. 8.
17.
Hubbard, J. Tetrahedron 1988, 29, 3197.
253
CHAPTER FOUR
Synthesis and Characterization of l,l1'-r 5-Bis(dimethylvinylsilylcyclopentadienyl)
Group 4 Metal Dichlorides
254
INTRODUCTION
Organometallic polymers are useful for a variety of applications including potential
catalysts, semiconductors, electrode coating materials.1 2 Two different routes can be used
to prepare the metal-containing polymers. One approach involves the derivatization of
preformed organic polymers with organometallic functionalities. Another approach
involves the synthesis of organometallic complexes that contain polymerizablefunctional
groups which then are used in homopolymerization or copolymerization. The latter
approach is more commonly used.
The vinylcyclopentadienyl monomers typically have been prepared by electrophilic
aromatic substitution reactions. 3 For example, (
5 -vinylcyclopentadienyl)
tricarbonylmanganese was obtained by the acetylation of the cyclopentadiene ring, followed
by reduction of the keto function and dehydration as illustrated below (eq. 1).3b'c
0O
OH
FjD
TIC-CH3
Mn
OC
CH 3 COC1
xCO AlCl3
co
¶
/
Em CHCH3
NaBH
Mn
co
co
4
Mn
OC
CO
co
(1)
p-TosH
2dMn
OC/ I \CO
CO
CH=CH 2
255
However, only a few cyclopentadienyl complexes can undergo electrophilic
aromatic substitution reaction, and many cyclopentadienyl complexes are not stable to
Friedel-Crafts reaction conditions. Several alternate routes have been developed. As
shown in eq. 2, Macomber et al.4 have reported that (-C
5 H4 CH=CH2 )W(CO)3CH 3 can
be obtained by the reaction of sodium formylcyclopentadienide with hexacarbonyltungsten,
followed by methylation at tungsten and Wittig synthesis.
NaC H O
Na
CHO
Na +
W
+ W(CO) 6
DMF
OC/I CO
co
CH 3 1
(2)
CHO
W-
CH3
/c IC
co
iCH=CH
Ph3PCH 3 + I-
5 N NaOH
W
OC/
CH3
Co
More recently, Macomber et al. have found that a reaction between 6-methylfulvene
and lithium diisopropylamide in THF solution afforded the new organolithium reagent,
vinylcyclopentadienyllithium.
A variety of vinylcyclopentadienyl monomers containing Ti,
V, Mo, Cu, W, Co, Rh, and Ir have since been prepared by the reaction of
vinylcyclopentadienyllithium
with the corresponding metal complexes.
reaction of vinylcyclopentadienyllithium with (
5
For example, a
5 -cyclopentadienyl)titanium
trichloride has
provided the first vinyl monomer of titanium, (r5-vinyl-cyclopentadienyl) (T5cyclopentadienyl) titaniumdichloride in low yield (16%) (eq. 3).
256
H
ICH=CH
2
CH 3
NaH
CH=CH 2
CpTiC13
(3)
'C1
*"C
Surprisingly, although many monovinylcyclopentadienylmonomers have been
prepared, so far only three l,l'-divinylmetallocene
monomers have been reported in the
literature. 6 , 7 Recently, l,l'-divinylcyclopentadienylvanadium
has been prepared by the
reaction of the lithium vinylcyclopentadienide with vanadium trichloride (eq. 4).7 No 1,1'divinylcyclopentadienyl monomers of the Group 4 metals have been reported.
H
CH3
CH--CH2
NNaH
1/3 VC13
4Q;-- CH=CH
2
ro
(4)
V
-- CH=CH 2
Diene compounds are very useful monomers for cyclopolymerization. The best
known transition metal diene complex, 1,l'-divinylferrocene, has been the subject of
numerous studies, and its cyclopolymerization has been studied extensively under radical
and cationic conditions.
8
We report here the synthesis and characterization of the first Group 4
divinylcyclopentadienyl monomers, 1,1'-bis(dimethylvinylsilyl)metallocene(IV)
dichlorides, (C5H4SiMe2CH=CH2)2MC12,(M = Ti, Zr, Hf). In addition, obis(dimethylvinylsilyl)benzene
prepared.
and l,l'-bis(dimethylvinylsilyl)ferrocene
also have been
257
RESULTS AND DISCUSSION
Preparation and Characterization of 1,1'-Bis(dimethylvinylsilyl)metallocene
(IV) Dichlorides, [(rl5 -CsH 4 SiMe 2 CH=CH 2) 2MC12] (M = Ti, 1, M = Zr, 2,
M = Hf, 3)
Antinolo et al have reported that the reaction of lithium
trimethylsilylcyclopentadienide
with a corresponding metal tetrachloride gives a series of
bis(trimethylsilylcyclopentadienyl)
Group 4 metal dichlorides (eq. 5) in good yield. 9
SiMe3
i+
1/2MCI4
,
M0
(5)
(5)
-LiCI
LiCi
Me 3 Si
C1
M = Ti, Zr, Hf
5
1,1'-Bis(dimethylvinylsilyl)cyclopentadienylmetal (IV) dichlorides, [(i S-
C 5 H4 SiMe 2 CH=CH 2) 2MC12] (M = Ti, 1, M = Zr, 2, M = Hf, 3), were prepared in a
similar manner. The dimethylvinylsilyl substituted cyclopentadiene,
C5H5SiMe2CH-CH2,10 was synthesized by reaction of Na[C5H 5] with
dimethylvinylchlorosilane in tetrahydrofuran. Metalation of the dimethylvinylsilyl-
substituted cyclopentadiene with n-BuLi, followed by the reaction of the anion with the
appropriate anhydrous metal (IV) chloride, affords the
bis(trimethylvinylsilyl)cyclopentadienyl
Group 4 metal dichlorides (Scheme 1) as white (M
= Zr, Hf) or red (M = Ti), air-stable crystals in 61-68% yield after recrystallization from
hexane.
258
Scheme
1
H
Na+
+
CISiMe2 CH=CH2
SiMe 2CH=CH 2
-N
n-BuLi
SiMe 2 CH=CH 2
di+
CHeCHMeSi2
1/2 MCI 4
MCHHMe2Si
wo
- LiCI
- Cl
CH 2 =CHMe
C1
2Si
1, M=Ti
2, M=Zr
3, M=Hf
Compounds 1-3 were fully characterized using 1H, 13C,and
29 Si NMR
spectroscopy, IR spectroscopy, mass spectroscopy, elemental analysis. The yields,
melting points, and elemental analyses are given in Table 1.
Table 1. Physical properties of 1-3
compound yield
mp
( C)
analysis: % calculated/found
C
H
1
61
134-135
51.80/51.91
6.28/6.30
2
3
68
65
99-100
95-96
46.93/46.70
39.46/39.77
5.69/5.73
4.76/4.85
259
The 1 H NMR spectral data for 1-3 are given in Table 2. Compounds 1-3 have
very similar 1H NMR spectra. Each compound exhibits two apparent triplets due to the
cyclopentadienyl protons as well as the typical ABX pattern for a terminal vinyl group. As
shown in the 1 H NMR spectrum of 2 (Figure 1), the =CHaHb protons
give two sets of doublets of doublets. The primary doublet is the result of cis-vicinal (Jbc=
14.6 Hz) or trans-vicinal (Jac= 20.0 Hz) coupling and the secondary doublets result from
splitting by the geminal protons (Jab= 3.6 Hz). The CHc= proton gives a doublet of
doublets. The primary doublets result from trans-vicinal coupling and the secondary
doublets are the result of cis-vicinal coupling. The 1 H NMR spectrum of 2 also shows one
SiMe resonance at 0.34 ppm. The
13C
NMR spectra data are consistent with the results
from the 1H NMR spectra. In the 29SiNMR spectra of 1-3, each of the compounds
exhibits only one signal for SiMe group.
Compounds 1-3 also were analyzed by electron impact low resolution mass
spectrometry. Selected m/z data are given in Table 3. The data show that the molecular
ions, M+ are observed in 1 and 2 but not 3. Loss of a CH3 and CH2=CH fragment is
observed in all cases, which are the two expected fragmentations in alkyl and vinyl-silyl
compounds. A M+ - CpSiMe2CH=CH2fragment was also observed for these
compounds.
In addition to the NMR spectra and mass spectrometry, 1-3 were analyzed by IR
spectroscopy. The IR spectral data are quite similar, exhibiting the characteristic stretches
for CH=CH2 (1590-1593 cm-l).
260
C
eq
U
c
·
m
mn
or 0[
I',
as
2
Lo
ZE
o
*;
:
bl
1c
B
261
Table 2.
1H
NMR spectra data for 1-3
Hb
\C
Ha
1CC
/
Nk2S
-Cl
MI'
CH 2 =CHMe 2Si -
'11
C
-
1,M=Ti, 2,M=Zr, 3,M=Hf
CompoundS (ppm)
1
-2.03
5.72
Mult
s
dd
J (Hz)
3.5 (Jab)
Area
Assignment
12
SiMe2
2
HbHa=HcSi
2
HbHa=HcSi
2
HbHa=HcSi
20.3 (Jac)
6.02
dd
3.5 (Jab)
14.9 (Jbc)
6.24
dd
14.9 (Jbc)
20.3
6.56
6.78
2
(Jac)
t
2.6 (3 J)
4
C 5 H4
t
2.7 (3J)
4
C 5 H4
12
SiMe2
2
HbHa=HcSi
2
HbHa=HcSi
2
HbHa=HcSi
0.34
5.69
dd
3.6(Jab)
20.0 (Jac)
6.0
dd
3.6 (Jab)
14.6 (Jbc)
6.27
dd
14.6 (Jbc)
20.0
(Jac)
6.46
t
2.4 (3 J)
4
C5H4
6.63
t
2.4 (3 J)
4
C 5H4
262
Table 2 continued
3
0.37
5.72
S
dd
3.6 (Jab)
12
SiMe2
2
HbHa=HcSi
2
HbHa=HcSi
2
HbHa=HcSi
4
4
C5H4
20.3 (Jac)
6.03
dd
3.6 (Jab)
14.6 (Jbc)
6.27
dd
14.6 (Jbc)
20.3 (Jac)
6.40
t
t
6.57
2.4 (3 J)
2.4 (3 J)
C5H4
Table 3. Selected mass spectrometry data for 1-3
compounds
1
( 4 8 Ti)
Calcd. mass
416
M/z Found (fragment: relative intensity)
416 (M + , 1)
401 (M+ -Me, 2)
389 (M+ - CH2=CH, 4)
267 (M + - C5H4SiMe2CH=CH2, 100)
2 ( 9 0Zr)
458
458 (M + , 4)
443 (M+ - Me, 62)
431 (M+ - CH=CH2, 40)
309 (M+ - CpSiMe2CH=CH2, 80)
3 (l 8 0 Hf)
548
533 (M+ - Me, 33)
521 (M + - CH2=CH, 20)
399 (M+ - CsH4SiMe2CH=CH2, 67),
263
Preparation and Characterization of o-Bis(dimethylvinylsilyl)benzene,
o-
(CH 2 =CHSiMe 2 ) 2 C 6 H 4 , 4
In 1963 Chaffee and Beck 11 prepared the o-bis(dimethylsilyl)benzene via an in situ
Grignard coupling of dimethylchlorosilane with o-dibromobenzene (eq. 6). This procedure
is known as the Barbier method,12 and it depends on the fact that silyl halides, with the
exception of arylsilyl halides, are unreactive towards magnesium.
Rr
A TV
W-
31.
Me2n
UJL
1, 2Mg
(6)
2, 2 MI2HSiCl
'aMg
.
U
LJ`%*2'
Br
o-Bis(dimethylvinylsilyl)benzene, o-(CH2--CHSiMe2)2C6H4,4, was prepared via
an in situ Grignard coupling of vinyldimethylchlorosilane with o-dibromobenzene.
A
solution of o-dibromobenzene in THF was added dropwise to the mixture of magnesium
turnings and 2.2 molar equivalents of vinyldimethylchlorosilane (eq. 7). The reaction
mixture then was refluxed for 18 h. A standard aqueous work up was followed by
fractional distillation to provide o-bis(dimethylvinylsilyl)benzene,
4, in 35% yield as a
clear, colorless liquid. The distillation residue was examined by 1 H NMR (Figure 2) and
was found to be composed of polymeric material. which explains the low yield of this
reaction.
Rr
I
a_
ErI
"l
, liMe2-I=UL 2
l
1, Mg
(7)
2, 2 CH--CHSiMe
Br
2 Cl
CI!'C. A
rT
IlT
ae1a 2 .Ln=L.r
2
264
o-Bis(dimethylvinylsilyl)benzene
was characterized by 1 H, 13C, and
2 9 Si
NMR
spectroscopy, IR spectroscopy, and elemental analysis. NMR spectral data are given in
Table 3. 1H NMR spectrum of 4 is shown in Figure 3. The vinyl pattern of
compounds 1-3 also was observed in the 1H NMR spectrum of 4. In the
13C
NMR
spectrum, the olefinic carbons CH=CH2 appear as a doublet and a triplet at 140.3 ppm and
132.2 ppm, respectively. The chemical shifts of these olefinic resonances are quite similar
to those found for 1-3. The 29 Si spectrum of 4 shows only one resonance for the SiMe2
groups.
265
I
0
1
0
0
0s
0I
0
Io
i
*R
-c
:3
_oX
Ca
cn
'-
0
a
,
co
0CA
0
2
l r~
II
?a
iz
TO
a
266
a.Z
-,3
N
I1
C
C
U
-
w
u
1o
4e
. oJ
to
0
$
.' co
7'o
.'
rZ
267
Table 4. NMR spectral Data for 4
HC\
Hb
Q7
SiMe 2
C
Ha
SiMe 2CH=CH 2
4
NMR
S
1H
J (Hz)
0.42
Mult
s
5.71
dd
3.7 (Jab)
Area
Assignment
12
SiMe2
2
CHaHb=CHc
2
CHaHb--CHc
2
CHaHb=CHc
20.6 (Jac)
6.04
dd
3.7 (Jab)
14.3 (Jbc)
6.40
dd
14.3 (Jbc)
20.6 (Jac)
13 C
2 9 Si
7.35
m
2
C 6 H4
7.69
m
2
C 6 H4
0.4
118.7
SiMe2
127.9
q
d
161.3
Ph
132.2
t
136.1
d
153.9
158.4
CH=CH 2
Ph
140.3
d
137.7
144.5
s
CH=CH2
Ph
-10.31
s
SiMe2CH--C
268
Preparation and Characterization of 1,1'-Bis(dimethylvinylsilyl)ferrocene,
(flS-CsH4SiMe
2 CH=CH 2) 2 Fe,
5
The preparation of 1,l'-bis (dimethylvinylsilyl)ferrocene, 5, has been reported
previously in low yield (31%) by the metalation reaction of ferrocene with n-butyllithium in
ethers, without any spectral data.10a
Two different procedures were employed in the present preparation of 1,1'-bis
(dimethylvinylsilyl)ferrocene, 5 (eq. 8). The first procedure (A) involves addition of
dimethylvinylchlorosilane to freshly prepared 1,l'-dilithioferrocene slurries (in situ use). 14
The other procedure (B) involves isolation of red-orange crystalline solids of
(C5H 4 Li) 2 Fe*TMEDA, 1 4 followed by the addition of the dimethylvinylchlorosilane to a
hexane solution of the lithium reagent. Procedure B leads to higher product yields, which
is likely due to the use of pure 1,1'-dilithioferrocene.
In both procedures, a standard
aqueous work up was used in the purification. The only side product, ferrocene, was
readily removed by vacuum sublimation. A red-orange oil, which was pure, was obtained
in 70% yield (procedure A) and 82% yield (procedure B),.
SZ=p
HSiMe
2CH=CH2
4SiMeH=CH
2
1, n-BuLi/TMEDA
2, 2 C
2
=CHClSiMe 2
1,l'-Bis(dimethylvinylsilyl)ferrocene,
and
2 9 Si
5, was characterized by 1 H, 13C,
NMR spectroscopy and IR spectroscopy.
1 H, 13 C
and
2 9 Si
NMR spectral data
are given in Table 5. The 1H NMR spectrum of 5 is quite similar to the 1H NMR spectra
of 1-3 except that the two triplets of cyclopentadienyl protons were observed upfield of
the terminal vinyl protons (Figure 4). The 13 C NMR spectral data for 5 are consistent
269
terminal vinyl protons (Figure 4). The 13 C NMR spectral data for 5 are consistent with
the results of the 1 H NMR spectrum and support the formulated structures for 5. Similar
to 1-4, only one resonance was observed for SiMe group in the
2 9 Si
NMR spectrum.
270
L
I
I
In
0
4
o
C
YC
cu
N
uC6~~C4
-
30
0
92
Kn
-0
C
2
_4
4
0
id
FM
-0
-
-
- =L
0
o
I-\-
I-I
to-
s
In
271
Table 5. NMR spectral Data for 5
Cr/
c=c-
Hc\
Hb
sz~jr SiMe
2 Ha
Fe
44--~SiMe
2CH=CH
2
NMR
8
Mult
1H
0.44
s
4.19
4.42
t
5.85
dd
J (Hz)
Area
Assignment
12
SiMe2
( 3 J)
4
C 5 H4
2.0 ( 3 J)
4
C 5 H4
3.3 (Jab)
2
CHaHb--CHc
2.0
20.2 (Jac)
6.12
dd
3.3 (Jab)
14.6 (Jbc)
2
CHaHb=CHc
6.43
dd
14.6 (Jbc)
2
CHaHb=CHc
20.2 (Jac)
13
29
C
Si
2.0
q
69.7
s
71.3.
d
174.3
C 5 H4
73.0
d
174.4
C 5 H4
132.3
t
150.2
CH=CH 2
140.3
d
134.4
CH=CH2
-15.4
s
119.7
SiMe 2
C 5 H4
SiMe2CH--C
272
EXPERIMENTAL SECTION
General Comments.
All reactions were performed under an inert atmosphere using standard Schlenk
techniques. All solvents were distilled under nitrogen from the appropriate drying agents.
Dimethylvinylchlorosilane
was purchased from Hills Inc. and distilled from magnesium
chips before use. n-Butyllithium in hexane was purchased from Aldrich and titrated for
RLi content by the Gilman double-titration method. 15 o-Dibromobenzene was purchased
from Aldrich and used without further purification. Tetramethylethylenediamine (TMEDA)
was purchased from Aldrich and distilled from calcium hydride before use. Group 4 metal
chlorides were purchased from Aldrich.
NMR spectra were obtained on a Varian XL-300 NMR spectrometer and listed in
parts per million downfield from tetramethylsilane.
13 C
and decoupled, were obtained at 75.4 MHz in CDC13.
NMR spectra, both proton coupled
2 9 Si
NMR spectra were recorded at
59.59 MHz in CDC13using tetramethylsilane as the external standard at 0.00 ppm.
Electobn impact mass spectra (MS) were obtained using a Finnigan-3200 mass
spectrometer operating at 70 eV. Infrared spectra (KBr and thin film) were obtained using
a Perkin-Elmer 1600 Fourier Transform Infrared spectrophotometer. Melting points of
analytically pure crystalline and solid products were determined in air using a Biichi melting
point apparatus. Elemental analyses were performed by the Scandinavian Microanalytical
Laboratory, Herlev, Denmark.
273
Preparation of 5-Dimethylvinylsilylcyclopentadiene, CsHsSiMe2CH=CH2,
(TW-I-66)
A 250 mL round-bottomed Schlenk flask equipped with a magnetic stir bar and a
rubber septum was charged with 4.6 g (0.2 g atom) of finely divided sodium sand and 100
mL of THF. To this solution at -78°C was added slowly by syringe 13.2 g (0.2 mol) of a
freshly distilled cyclopentadiene. The resulting mixture was stirred for 1 h, then
dimethylvinylchlorosilane (24 g, 0.2 mol) was added over 30 min. After further stirring
for 4 h, the mixture was hydrolyzed with distilled water (100 mL). The organic layer was
separated and the aqueous layer was extracted twice with Et2O (2 x 50 mL). The combined
organic layers were dried over MgSO4 and all volatiles were removed at 25°C/25 mm Hg.
The residue was distilled to yield (dimethylvinylsilyl)cyclopentadiene
(18 g, 60%) bp
74C/25 mm Hg (lit10a 530 C/17 mm Hg). This material was stored at -30°C until required
for use.
1H
NMR (300 MHz, CDC13): 6 0.04 (s, 6 H, SiMe 2 ), 3.11 (s, 1 H, C 5 H 5 ), 5.58-6.48
(m, 3 H, CH=CH2), 6.65 (m, 4 H, CsH4)
5
Preparation of Lithium Dimethylvinylsilylcyclopentadienide(TW-I-68)
To freshly distilled 5-dimethylvinylsilylcyclopentadiene(2.3 g, 15.3 mmol) at 78°C in hexane (80 mL) was slowly added with mechanical stirring (ca. 15 min.), n-BuLi
in hexane (7.7 mL, 2.06 M). The solution became viscous after removing the dry ice bath
and a white precipitate of lithium dimethylvinylsilylcyclopentadienide
was deposited. After
stirring at room temperature for lh, the white precipitate was collected by filtration and
washed twice with hexane (2 x 50 mL) to give a white powder. Drying in vacuo overnight
yielded a fine white powder (2.2 g, 92%).
274
Preparation of 1,1'-Bis(dimethylvinylsilylcyclopentadienyl)titanium
Dichloride,
1 (TW-I-40)
A 250 mL round-bottomed Schlenk flask equipped with a magnetic stir bar and a
rubber septum was charged with 1.85 g (11.9 mmol) of lithium
dimethylvinylsilylcyclopentadienideand 100 mL of THF. To this solution at 0°C, a
solution of TiC14(1.12 g, 5.9 mmol) in 30 mL of THF was added slowly by cannula with
stirring over 15 min. The resulting mixture was stirred at 25°C overnight. Removal of
solvent in vacuo, followed by extraction with boiling hexane (2 x 100 mL), filtration,
concentration of the filtrate to ca. 100 mL, and cooling to -230 C gave red needles of
complex 1 ( 1.48 g, 61%), mp 134-135 0 C.
1H
NMR (300 MHz, CDC13 ): 8 -2.03 (s, 12 H, SiMe2), 5.72 (dd, 2 H, Jab = 3.5, Jac =
20.3 Hz, HbHaC=CHcSi), 6.02 (dd, 2 H, Jab = 3.5, Jbc = 14.9 Hz,
HbHaC=CHcSi), 6.24 (dd, 2 H, Jbc = 14.9, Jac = 20.3 Hz, HbHaCCHcSi),
6.56 (t, 4 H,
1 3C
3
= 2.6 Hz, C 5 H4), 6.78 (t, 4 H,
3
= 2.7 Hz, C 5 H4).
NMR (75.4 MHz, CDC1 3 ): 8 -2.0 (q, J = 120.5 Hz, SiMe 2 ), 120.4 (d, J = 172.1
Hz, C 5 H4), 129.7 (d, J = 177.4 Hz, C 5 H4), 130.4 (s, C 5 H4), 132.8 (t, J =
153.6 Hz, CH2--CHSi), 138.1 (d, J = 138.5 Hz, CH2=CHSi).
2 9 Si
NMR (59.59 MHz, CDC13 ): 8 -13.5.
MS Calcd for C18H26 TiCI2Si2:416 (48 Ti), Found: (EI, 48Ti); m/z (relative intensity): 416
(M + , 1), 401 (M + - Me, 2), 389 (M+ - CH2=CH, 4), 381 (M + - Cl, 6), 267
(M + - CSH4SiMe2CH=CH2, 100), 206 (21), 174 (20), 149
(CsH4SiMe2CH=CH
(40).
2,
18), 119 (23), 93 (38), 85 (SiMe2CH--CH2, 24), 59
275
IR (KBr, cm- 1): 3083(w), 2951(m), 1593(w, C=C), 1405(s), 1373(m), 1246(s), 1173(s),
1107(s), 1051(s), 1014(m), 956(s), 924(w), 898(m), 865(m), 808(s), 773(s),
707(m), 620(w).
Anal. Calcd for C18 H26 TiCl2Si2: C, 51.80; H, 6.28. Found: C, 51.91; H, 6.30.
Preparation of 1,1'-Bis(dimethylvinylsilylcyclopentadienyl)zirconium
2 (TW-I-69)
Dichloride,
A 250 mL round-bottomed Schlenk flask equipped with a magnetic stir bar and a
rubber septum was charged with 1.85 g (11.9 mmol) of lithium
dimethylvinylsilylcyclopentadienide
and 100 mL of THF. To this solution at 0°C, a
solution of ZrCI4 (1.38 g, 5.9 mmol) in 30 mL of THF was added slowly by cannula with
0
stirring over 15 min. The resulting mixture was stirred at 25 C overnight. Removal of
solvent in vacuo, followed by extraction with boiling hexane (2 x 100 mL), filtration,
concentration of the filtrate to ca. 100 mL, and cooling to -23°C gave colorless needles of
complex 2 ( 1.85 g, 68%), mp 99-100 0 C.
1H
NMR (300 MHz, CDC13): 8 0.34 (s, 12 H, SiMe2), 5.69 (dd, 2 H, Jab = 3.6 Hz, Jac
= 20.0 Hz, HbHaC=CHcSi), 6.0 (dd, 2 H, Jab = 3.6 Hz, Jbc = 14.6 Hz,
HbHaC=CHcSi), 6.27 (dd, 2 H, Jbc = 14.6 Hz, Jac = 20.0 Hz,
HbHaC=CHcSi), 6.46 (t, 4 H, 3J = 2.4 Hz, C5 H4), 6.63 (t, 4 H, 3j = 2.6 Hz,
C 5 H4).
13C NMR (75.4 MHz, CDC13): 8 -2.1 (q, J = 120.4 Hz, SiMe2), 116.7 (d, J = 167.4
Hz, C 5 H4), 124.0 (s, C 5H4), 125.9 (d, J = 173.9 Hz, C 5H4), 132.8 (t, J =
150.1 Hz, CH2 =CHSi), 138.1 (d, J = 137.4 Hz, CH2 =CHSi).
276
29Si NMR (59.59 MHz, CDC13 ): 8 -14.2.
MS Calcd for C18H26 ZrCl2Si2: 458 (9 0Zr), Found: (EI, 9 OZr); m/z (relative intensity): 458
(M+ , 4), 443 (M+ - Me, 62), 431 (M+ - CH2-CH, 40), 423 (M+ - Cl, 2), 309
(M + - C5H4SiMe2CH=CH2, 84), 281 (10), 149 (CsH4SiMe2CH=CH
2,
5),
119 (5), 97 (6), 85 (SiMe2CH=CH2, 6), 71 (11), 57 (20)
IR (KBr, cm-1): 3080(w), 3051(w), 2949(m), 1591(w, C=C), 1403(s), 1369(m),
1317(w), 1246(s), 1199(w), 1172(s), 1045(s), 1013(m), 957(s), 900(w),
829(s), 808(s), 773(s), 705(m), 619(w).
Anal. Calcd for C18H26ZrCl2Si2:C, 46.93; H, 5.69. Found: C, 46.70; H, 5.73.
Preparation of 1,1'-Bis(dimethylvinylsilylcyclopentadienyl)hafnium
Dichloride,
3 (TW-I-74)
A 250 mL round-bottomed Schlenk flask equipped with a magnetic stir bar and a
rubber septum was charged with 1.85 g (11.9 mmol) of lithium
dimethylvinylsilylcyclopentadienideand 100 mL of THF. To this solution at 0° C, a
solution of HfCI4 (1.89 g, 5.9 mmol) in 30 mL of THF was added slowly by cannula with
stirring over 15 min. The resulting mixture was stirred at 250 C overnight. Removal of
solvent in vacuo, followed by extraction with boiling hexane (2 x 100 mL), filtration,
concentration of the filtrate to ca. 100 mL, and cooling to -23°C gave colorless needles of
complex 3 ( 2.1 g, 65%), mp. 95-96 0 C.
1H
NMR (300 MHz, CDC1 3): 8 0.37 (s, 12 H, SiMe2), 5.72 (dd, 2 H, Jab= 3.6 Hz, Jac
= 20.3 Hz, HbHaC=CHcSi), 6.03 (dd, 2 H, Jab = 3.6 Hz, Jbc = 14.6 Hz,
277
HbHaC=CHcSi), 6.27 (dd, 2 H, Jbc = 14.6 Hz, Jac = 20.3 Hz,
HbHaC=CHcSi), 6.40 (t, 4 H, 3j = 2.4 Hz, C5H4 ), 6.57 (t, 4 H, 3J = 2.5 Hz,
C5H4).
13C
NMR (75.4 MHz, CDC1 3): 8 -2.0 (q, J = 120.8 Hz, SiMe 2 ), 115.4 (d, J = 165.8
Hz, C 5 H4), 121.5 (s, C 5 H4), 124.8 (d, J = 174.0 Hz, C5H4), 132.7 (t, J =
149.0 Hz, CH2=CHSi), 138.1 (d, J = 136.0 Hz, CH2=CHSi).
29Si NMR (59.59 MHz, CDC13 ): 8 -14.2.
0 Hf), Found: (EI,
MS Calcd for C18H26 HfCl2Si2: 548 (18
180 Hf);
m/z (relative intensity):
533 (M + - Me, 33), 521 (M + - CH2=CH, 20), 413 (11), 399 (M + CsH4SiMe2CH=CH2,
67), 387 (8), 371 (18), 359 (7), 341 (5), 315 (22), 149
(C 5 H4SiMe2CH--CH2, 5), 119 (56), 93 (50), 85 (SiMe2CH=CH 2 , 67), 73
(18), 59 (100)
IR (KBr, cm-l): 3083(w), 3052(w), 2950(m), 1592(w, C=C), 1404(s), 1371(m),
1318(w), 1247(s), 1173(s), 1046(s), 1014(m), 957(s), 903(w), 853(s),
833(s), 809(s), 773(s), 705(m), 620(w).
Anal. Calcd for C18H26HfCl2Si2:C, 39.46; H, 4.76. Found: C, 39.77; H, 4.85.
Preparation of o-Bis(dimethylvinylsilyl)benzene,
4 (TW-I-26, 33, TW-V.
28)
In a 500 mL, three-necked, round-bottom flask equipped with a mechanical stirrer,
a 100 mL, pressure equalizing addition funnel, and a reflux condenser with an argon inlet,
were placed 3.7 g (153 mmol, excess) magnesium turnings, 150 mL of THF, and 17.58 g
278
(145.9 mmol) of dimethylvinylchlorosilane. A THF (30 mL) solution of oDibromobenzene(15.65 g, 66.3 mmol) was added dropwise at a rate such that the reaction
temperature remained at ca. 500. The reaction mixture was then refluxed for 14 h. The
reaction mixture was diluted with 50 mL of hexane and hydrolyzed with saturated, aqueous
ammonium chloride solution. The organic layer was separated, washed with water, and
dried over anhydrous sodium sulfate. All volatiles were removed by evaporation under
reduced pressure (0.1 mm, 250 C). The concentrated reaction mixture was short path
distilled in vacuo to yield 5.7 g (35%) of o-bis(dimethylvinylsilyl)benzene:
bp 62-64°C
(0.03 mm)
1H
NMR (300 MHz, CDC13 ): 8 0.42 (s, 12 H, SiMe 2 ), 5.71 (dd, 2 H, Jab = 3.7 Hz, Jac
= 20.6 Hz, HbHaC--CHcSi), 6.04 (dd, 2 H, Jab = 3.7 Hz, Jbc = 14.3 Hz,
HbHaC=CHcSi), 6.40 (dd, 2 H, Jbc = 14.3 Hz, Jac = 20.6 Hz,
HbHaC--CHcSi), 7.35 (m, 2 H, C6 H4), 7.69 (m, 2 H, C 6 H4).
13 C
NMR (75.4 MHz, CDC13 ): 8 0.4 (q, J = 118.7 Hz, SiMe2), 127.9 (d, J = 161.3
Hz, meta-C6H4), 132.2 (t, J = 153.9 Hz, CH2--CHSi), 136.1 (d, J = 158.4
Hz, ortho-C6H4), 140.3 (d, J = 137.7 Hz, CH2=CHSi), 144.5 (s, C6 H4 ),
2 9 Si
NMR (59.59 MHz, CDC1 3 ): 8 -10.3.
IR (Thin Film, cm-l): 3111(w), 3067(w), 3046(s), 2952(s), 2899(m), 1901(w),
1592(w, C=C), 1449(w), 1403(s), 1248(s), 1169(w), 1149(w), 1116(m),
1053(m), 1007(s), 950(s), 823(s), 773(s), 742(s), 696(s).
Anal. Calcd for C14H22Si2:C, 68.22; H, 9.00. Found: C, 68.48; H, 8.87.
279
Preparation
of 1,1'-Bis(dimethylvinylsilyl)ferrocene,
5 (TW-I-17, 29, 31,
32)
Method A: A mixture of N,N,N',N',-tetramethylethylenediamine (38.2 g, 0.33
mol) and a solution of n-butyllithium in hexane (277 mL, 2.06 M) was added with stirring
over a half-hour period to a solution of ferrocene (50.9 g, 0.27 mol) in 1400 mL dry
hexane under nitrogen in a 3-liter, three-necked flask equipped with a stirrer, nitrogen inlet
and reflux condenser.. The solution was stirred for 4 h at room temperature under nitrogen
and then a solution of dimethylvinylchlorosilane (60 g, 0.5 mol) in 100 mL hexane was
added dropwise over a 40 minute period with constant stirring. The reaction mixture was
further stirred under nitrogen overnight. To the resulting mixture, 200 mL of distilled
water was added. The organic layer was separated and the aqueous layer was extracted
twice with hexane (2 x 100 mL). The combined organic layer was dried over MgSO4 and
all volatiles were removed using a rotary evaporator. A red-orange oily residue was
obtained. Ferrocene was removed by heating this red-orange residue at 500 in vacuo (0.03
mm) and a red-orange oily product, 5, was obtained (78 g, 70%).
1H
NMR (300 MHz, CDC13 ): 8 0.44 (s, 12 H, SiMe2), 4.19 (t, 4 H, 3J = 2.0 Hz,
C5H4), 4.42 (t, 4 H, 3 J = 2.0 Hz, C5H4), 5.85 (dd, 2 H, Jab = 3.3 Hz, Jac =
20.2 Hz, HbHaC--CHcSi), 6.12 (dd, 2 H, Jab = 3.3 Hz, JbC= 14.6 Hz,
HbHaC=CHcSi), 6.43 (dd, 2 H, Jbc = 14.6 Hz, Jac = 20.2 Hz,
HbHaC=CHcSi).
13 C
NMR (75.4 MHz, CDC13 ): 8 2.0 (q, J = 119.7 Hz, SiMe2), 69.7 (s, C 5H 4 ), 71.3
(d, J = 174.3 Hz, C 5 H 4 ), 73.0 (d, J = 174.4 Hz, C5H4), 132.3 (t, J = 150.2
Hz, CH2=CHSi), 140.3 (d, J = 134.4 Hz, CH2=CHSi),
2 9 Si
NMR (59.59 MHz, CDC13): 8 -15.4.
280
IR (Thin Film, cm-1 ): 3089(w), 3046(m), 3007(w), 2956(s), 1592(w, C=C), 1422(m),
1403(s), 1382(w), 1364(w), 1301(w), 1246(s), 1181(m), 1164(s), 950(s),
897(w), 863(m), 805(s), 773(s), 699(s), 618(s).
Method B A mixture of N,N,N',N',-tetramethylethylenediamine (38.2 g, 0.33
mol) and a solution of n-butyllithium in hexane (277 mL, 2.06 M) was added with stirring
over a half-hour period to a solution of ferrocene (50.9 g, 0.27 mol) in 1400 mL dry
hexane under nitrogen in a 3-liter, three-necked flask equipped with a stirrer, nitrogen inlet
and reflux condenser.. The reaction mixture became warm and a deep cherry red solution
was obtained. The reaction mixture was further stirred under nitrogen overnight. The
resulting mixture was filtered and the filtrate was washed twice (2 x 100 mL) with hot dry
hexane. Drying in vacuo afforded a fine orange powder (75 g, 89%). To this orange
powder in hexane (500 mL), a solution of dimethylvinylchlorosilane (60 g, 0.5 mol) in
hexane (100 mL) was slowly added. The reaction mixture was further stirred under
nitrogen overnight. A similar work up procedure was performed. Compound 5 was
obtained in 82% yield.
281
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283
ACKNOWLEDGMENTS
I would like to thank the following people for helping me to make this thesis possible:
Professor Dietmar Seyferth for supporting me for the past four years. His
encouragement and his constant interest in my work were the best things that could
happened to me.
Professor Patty Wisian-Neilson, my M.S. thesis advisor at Southern Methodist
University, for giving me the opportunity to come to the United States and work in her
group, and for introducing me to the organometallic chemistry.
David Son, my labmate for three years, a great friend in my life, for all those good
time in the lab, for always being there when I need your help. You made my graduate
study at MIT more enjoyable. Things were never quite the same after you left. I would
also like to express my gratitude for his help in editing this thesis.
Dr. Keiji Ueno, for helping me get started on silicon chemistry.
Former Seyferth group members: Jenny Robison, Craig Masterman, Jamie
Gardner.
Current Seyferth group members: Shane Krska, Pawel Czubarow, Toshiya
Sugimoto.
Terry King for all her assistance and computer expertise. Thanks for the sport's
pages for three years. I will miss it very much!
Jackie Acho, a good friend of my family, for her friendship, for sharing the tension
and excitement away from chemistry, for those wonderful time to play cards (Tao's game)
and casino (craps).
David Bem, for willingly undertaking the horrible task of proofreading this thesis
and getting chapters back to me so quickly, also for being a great friend and another
enthusiastic craps player. We have to meet Jackie at Las Vegas soon.
284
I also want to acknowledge the support of my parents, even though they are far
away and probably never understood exactly what I was doing here, they taught me the
fundamentals of success: working hard and perseverance.
Finally, to my wife, Shihong and my sons, Chong and Kevin for their love,
encouragement and unbelievable support through these difficult years especially during the
preparation of this thesis. I couldn't have done it without them.
we made it !!!